ThreeDeadZs

John's right, and a professional. So I'll give you a "layman's" answer since I first toyed with that exact idea >25 years ago (Nissan/Toyota pickup instead of S10): Any pickup ladder frame is strong. It won't break because it is designed to bend. I'll bet your V8 S10's were fun... drifting an empty rear end. If that's what you want to do, maybe a Vega or Monza body might be appropriate for brand consistency. It also wastes a lot of space. It won't be torsionally rigid, so will handle like... a pickup truck! Get a fabricator to build you a full cage for your 240Z to carry torsional strength, or as John (a fabricator!) suggests, stick with the unibody. Seam welds, weak points to improve, etc, are all covered elsewhere on this site.; or just hire a fabricator. But assuming that (like me) you are pinching pennies and wishing to build something unique... well, I haven't found the combination yet. The closest I've come up with so far, with the help of a local Miata/BMW fabricator and circuit racer for ideas, is to CAD design a pair of tubes that attach the unibody to subframes of your choice (with easy connection points, which is the only reason I've considered Mazda) and get a machine shop to build them, then take them to the fabricator to build... a reinforced unibody! Really, it's nearly back where it started. I watch this thread hoping for a magic solution. For the sake of the thread: I did learn that Miata MX-5 subframes work well with a longer wheelbase, making the car more stable, and fine tune by changing front/rear wheel offsets. Later RX8/Miatas use multi-link rear ends, so not likely to be as easy to adapt.

Ouch! Thank you Tony for the reality check, I guess. Sorry but I don't know what CVC stands for. However, what you wrote in this quote sounds very interesting. I suppose I could complete the non-engine combination (using the original shell's correct engine & smog equipment) so my potential of mis-matched VIN's on undercarriage body panels or wherever don't cause a violation. (showing proof of ownership of both vehicles, I'm sure) Because I did research kit cars, modified cars, and such, and the DMV makes it perfectly clear that swapping a lot of equipment, as long as it isn't smog related or make the car unrecognizable as it's actual model, is perfectly legal. Yet, especially on newer parts, VIN numbers are everywhere. But on the L28 engine you used as an example in a 240Z, there's merely a model number (L28) and a serial number, no VIN. So what does that mean related to this CVC, and suppose I did your example: am I able to legitimately comply with these requirements without having to change to EFI and the newer engine's smog laws? And what about an engine that never came to the USA? I mean specifically the SR20DET, RB26DETT, CA18DET. A question of a different sort: suppose I keep the correct block for the smog exempt car, and modify the hell out of it with custom equipment, different head, turbo, custom piping, custom intake manifold, and whatever, maybe EFI; yet maintain whatever requirements they might have for the year... EVAP compliance, EGR, PCV, and not sure what all. Is there a way to do that so it complies with the law? Also, when they checked your VIN those four times, did they merely check the dash vin and maybe engine-bay firewall VIN, maybe doorjam? Or did they look for every VIN number they could find on parts throughout the body? I'm all for catching thieves, but what you've described doesn't seem to serve theft recovery or SMOG. You also mentioned the "VIN" on the engine, which only began more recently. As I say, my 97 Acura has a VIN plate on the transmission 1/2" from the engine. So if I swap transmissions, who would I have to report that to? BTW: you seem to have some sort of inside scoop on this... "Having worked task force where cars are impounded daily...." May I ask more about that? I asked you a lot, answer by post or PM for that which doesn't benefit the forum.

This has happened to you four times? I've never had it happen, or seen it happen in California. Saw it happen once in Missouri in the 1980's (I don't think there was a smog law) just to make sure nothing was from stolen cars. May I ask what your car is, and what might be special about it, that gets so much CHP attention? I have had (and I'm not boasting, in fact far from it, as I buy old broken cars, fix them and use them for a while, tire of them and sell them in working condition, getting something newer) more cars than I can remember. Certainly over 20. How many did I swap the engine? Maybe half of them (all legitimate swaps to the same model year) but I never reported any of them, and they subsequently passed smog; every single one. Smog guys checked the engine model of the block. I've made a few hybrids (or Frankenstein builds) and they are never caught as such. One smog guy was floored when he reported to me that my Honda Civic was running cleaner than brand new model year cars, and it was ten years old. (That Frankenstein was in a car that Honda got approved to have no cat (because of some strange exhaust manifold that burned waste gas, and I had a secondary cat from a newer larger car in the pipe, I may have also built the engine for higher compression, and used a better head). That was back before things got so stupidly strict (the car ran extremely clean and fast, but I re-engineered it, could go from a full stop to 90mph in second gear) What you are saying about swapping the model (like putting a B18C1 in my B18B1 Acura without reporting it) will get my car crushed. You are absolutely right about that. Funny thing about the VIN on my Honda - it is on the transmission bell-housing, not the engine. Older cars don't have VIN's on the engines. Putting a regulated engine into an unregulated car; I'm pretty sure they are coming down hard on that, which of course is exactly what I'm proposing - so I could get busted. With the car being exempt, do you know what the ramifications are? Ten days to take it to a Star Station, and swap back in an exempt engine before it; I could plan for that. Any pre-smog engine into any pre-smog body is supposed to be okay, but I suppose I'm supposed to have the expected smog equipment installed. I don't know about reporting requirements. I should look into that. Complete suspension swaps, interiors, and body as long as it is still recognizable as it's original model - are all completely okay without reporting changes. I do know that. All for now, I'm never up this late.

Update: I've been doing lots of reading! Gathering bootleg copies of Factory Service Manuals, writing up comparisons, looking for the best "interface" between the bodies and subframe designs, checking out Locost projects, and even (no kidding) considering building a kit car. It still comes back to my original premise, I'd like a "pre-smog" CA car with an SR20DET and a suspension to handle it. (with the caveat that I could be randomly inspected, right John?) Also had a conversation with the guy who used BMW M3 components, and learned how his car is build for high speed stability and a very involved build, and that the M3 subframes would not be suitable nor economical for a swap for me, as I'm interested in low speed performance. I came to the conclusion that for a 240Z or a 510; there's no substitute for a stock-based suspension with the ordinary upgrade paths done a million times. Calculated/estimated something I found surprising: subtract the entire drivetrain and suspension from a 240Z and a 510, and end up at nearly the same weight, with additional weight savings available for the 240Z (a front airdam is a must for high speed stability, and lightweight 240Z body kits are widely available), so really a 240Z is more suitable to a cheap or late model 4-banger conversion than a 510 if you don't need the interior room, which moves the weight to the rear for low speed performance (autocross), and the 240Z suspension and brakes will perform better by the ratio of how much it is lightened from stock. RB2xDET(T) is all the rage, but a SR20DET or better and more money a SR20VET hybrid are excellent, even a QR25DE RWD 2007+ based build (that's a complex subject of it's own), basic SR20DE, and so many other engines that are lighter than the L series it isn't worth listing them. Back to the ultra-light bodies using replacement subframes, which is the point of this thread: a Datsun 1200 [b110] weighs only 1600 lbs stock. Miata subframes (thus suspension, steering, and brakes) perform extremely well in autocross in the stock Miata which start at 2100lbs. The much cheaper and easier to find (including parts) Datsun B210 (1975-1979, I'd only use 1975 for smog reasons) weighs 2000lbs. 1975 likely had those huge mandated crash bumpers and other 'debris' which could be removed to save a lot of weight. So while Fugly (F* ugly), the B210 could use a cosmetic make-over, and likely fit even an SR20DET. It is worth mentioning that someone who likes them could do this with a Datsun 1600 Roadster (though the results are hard to estimate, since that Datsun weighs 2000lbs with an old style ladder frame and solid axle rear). Miata subframes alone are really easy to fabricate connections for, with connections 880mm apart. Classic Datsuns had front rails much closer together, and the rear "supports" are hopelessly complex shaped to attach anything to. I spent some time on the locost forum, and talking to a manufacturer of Miata based kit cars - didn't really get anywhere, though communicated with some nice people. Here's where it is at now: 1. I'm ready to give up, buy a 240Z stock, do ordinary suspension upgrades, build a platform to hold my dog partially into the passenger seat area, level with the rear floor, and have no passenger seat. Groceries go up front. That's pretty much what I do now with another car. 2. Custom tube frame to hold the Miata subframes into the Datsun body and hold the really simple Miata subframes, gutting the engine compartment completely, and rear seats get replaced with a long rear floor for a long hatchback. Going this custom, may as well move the front subframe as far forward as possible to increase engine bay space, and move the rear subframe as far forward as possible to minimize and hopefully match the wheelbase to the Miata. Rear gets gutted of all complexity, fuel cell goes just behind the suspension, spare tire mounts below floor behind that, bar goes across so a rear end accident crushes the rear body first and the spare tire, by the time it hits the fuel cell I'd be already be dead in a stock car. Likely out of my price range, but perhaps a very straightforward project. I learned a method of easily increasing the steering link length from the Locost (Lotus 7) sources. And finally: 3. This is what I'd like to explore which is directly related to the purpose of this thread (this is just my own idea, so fabricators, if I'm totally wrong, chime in but please don't flame me!): 3a. At least locate a Datsun B110 or B210 to measure periodically, not necessarily buying one for the project yet. Or buy a cheap junker with good body panels but not floor or drivetrain. Compare the stock distance of the floor and body panels of the Datsun to those of the Miata ( I don't yet have that comparison, but will try to get them soon ). If the Datsun is more than 3" higher than the Miata, then consider "only" lowering the Datsun 3" and increase the custom framerail depth by the additional height under the floor of the resulting project, thereby increasing the bending strength of the project. 3b. Buy a complete Miata that is worthless (best donor is supposedly 94+ because suspension and brakes increased when they increased the engine size, but if using much wiring you might avoid OBDII from 1997 on) and sell off all the cosmetics, interior, all removable body panels, (and after complete body removal, which is easiest with the engine, transmission , PPF, and front and rear suspension systems intact) sell the engine, transmission and differential unless you like that gearing and aren't putting out too much power. Hopefully this actually profits, instead of costing money, and you end up with a shell. Remove the gas tank, but might not use it. Flip the body over without damaging the chassis near it's floor. Support the front and back so you can chop up the frame-rails without the body bending (though the transmission tunnel and rocker panels are substantial). With everything intact, cut the framerails perfectly flat to the floorboard, so it can be replaced with two pieces of square tubing. 3c. Determine the Datsun's best (I figure forward-most) position for the rear Miata suspension, when converted to a 2 seater plus long hatch. Then determine the forwardmost reasonable position for the Miata's front suspension for all clearances, or further back if you prefer. Calculate this distance and compare to stock Miata's 2270mm. If equal or less, then stick to stock Miata geometry exactly. If longer, you'll need to cut the Miata 'jig' in half and lengthen it and support it rigidly. 3d. Weld the box frame rail replacements to the front and rear framerails, but not to the floor. Add doubler plates if necessary to maintain the strength from front/rear frame rails to the box frame (soon to be) floor frame rails. Find a couple of locations for initial crossmembers while still mounted to the chassis. That might be a "K" support at the front or rear, or if not able to be determined at this time, keep the rear floor installed and even spot weld a temporary 'top' under the front and even temporarily install the bare suspension subframes. 3e. Chop the Miata away from your newly minted pair of framerails keeping extra with teh framerails until you know you don't need it: for example, the entire inner wheelwells with shock mounts, and ease the framerails to the floor right side up. Cost up to this point if enough Miata parts are sold: labor and some steel. 4a. Take a Datsun body with all the hard to find trim and glass (B110 or B210) bought cheap, remove the front fenders and grill for reuse, and gut the car from in front of the firewall, though consider maintaining the sheetmetal that supports the fenders, and the support to the front supports (cut less now, so as not to add it back in later). Do the same behind the driver's compartment (everything from the floor down, including wheelwells and strut towers, after taking off the door(s) and preparing points for an engine hoist to lift the body from near it's cG (an adjustable hoist would help). It is better to cut away too little and figure out what is needed. 4b. Test fit the body to the frame, and cut the body back each as required for clearances. The body and frame will eventually be welded, so the frame need not be completely outside the body. Add doubler plates to the framerails. Continue test fitting and perfecting the measurements, maintaining the body straight and level relative to the frame. When satisfied everything fits, tack weld (and eventually seam weld) all connection points. With the front suspension forward, a filler box will be needed to extend the front framerails to the firewall. 4c. Having clear indication of the correct location, install substantial "K" crossmembers at the front and rear of the car, install a rear floor welded to the quarter panels and then mount the car on a rotisserie. After the body is clearly self-supporting on the rotisserie, remove the Miata subframes again, and finish out reinforcing the car's framing with crossmembers, fuel cell support, rollbar (supported by sheetmetal to the body all the way around makes it into a bulkhead). No doubt I've missed some steps. 4d. complete the project with engine/transmission mounts, plumbing, wiring (the Datsun wiring could be reused), support for the fuel cell, front body work, and around 3" of fender flaring, but if building such a monster, may as well give it more to allow giant tires. (9" wide tires on a ~2000lb car???!!) 5. After making sure the rolling chassis works well (even driving for a while with some readily available engine), build it up for a SR20DET!!! One thing I did not address is that if space allows, install the springs/struts inboard with rockers, or using long coil-overs that mount according to the body instead of the stock Miata tops, or a custom choice in between. Likewise, I did not specify any use of a rollcage, but just mentioned a single rollbar. Nor did I mention that because there would no longer be a narrow sheetmetal engine bay, that coolers could be located and vented more like a racecar. This is not meant to be considered complete. I basically put my proposal down into steps. This is completely open to constructive criticism. "Just buy a 240Z" is not constructive. The thing is, if I cannot pull off this very detailed build, I AM going to "just buy a 240Z." I'd really like to know if this can be completed as I've described it, or perhaps in some superior and more economical fashion. Having a car at 1600-2000lbs with Miata based suspension, pre-smog, with a massive engine bay (and enclosed hatchback) would be a riot. Blowing away the best of them with one of the slowest cars of the 70's (the B210) would be hilarious. Whether or not I build it, I'd like this thread to be the basis so someone else can.

John Coffey: I've always planned on whatever I build to be clean, so it will pass the tailpipe and EVAP tests, like including a high flow cat in a custom exhaust when the body never even had a cat, and having all the functions they look for working. I'm going to try to make it even pass a visual from less knowledgeable or lenient inspectors, since each purpose they will look for will actually be working, and the emissions will be low. I may even use a pre-smog block model, but build a Frankenstein, NA or Turbo. I'll paint and dress it according to what they expect, maybe even use the timing cover and valve cover that they expect. Only time and such a test will tell whether I get away with it. Another point about being "smog exempt" is that as long as they don't cite the vehicle or change it's status, it would not be required to precisely match stock, or go through the trouble and expense of biennial inspection. It could even be parked for a few years and stay paid up and registered without inspection. Datsun 1200: I've studied this as far as I can on paper, and inspecting a Miata at the junkyard. Big problem: Distance between door-skins is a few inches less than a Miata. This means I cannot use the Miata floor with it's huge transmission tunnel and manage to fit any seats in the car. Fabrication would have to be completely custom using the 1200's unibody complete, plus completely custom front snout, rear tub, rollbar and reinforcements. Using the Miata gas-tank allows using that section of Miata floor, with no equipment behind the suspension. There may be an advantage to offsetting the front and rear suspensions forward as much as a foot (using a fuel cell or stock tank), custom flaring new wheel-wells. That would give the 1200 a massive engine bay behind the front suspension, move the weight bias back, but require a custom steering rod and hope for no interference. The engine mounts would of course have to be custom, but that's the easy part. I'm still pursuing it, but have my doubts. Peej410's use of BMW E36 M3 suspension would be especially suitable to a 2/2 (2+2), assuming I can find a 1974 or 1975 body (260Z, 280Z), because the wheelbase can be made to exactly match by extending the wheelbase 5" (requiring additional custom fabrication), particularly if the front suspension can be moved forward as much as possible. I may explore that if the 1200 falls through.

I don't know what individual Miata is being mentioned (SCCA SOLO II winner for $6K), but I did say from the beginning that this is to be a daily driver for me and my giant dog in the mountains. A roadster would not work. Miata hardtop coupe (MEVX5 body kit) is interesting. I also mentioned that I want a body that is not smog inspected. If it weren't for CA SMOG, I'd buy a S14 240SX and swap in the SR20DET that should have been put in the USDM Sylvia in the first place. JohnC: If I get ten days to take it to a STAR test center, If I keep a stock-like engine in storage, and set the car up for quickly mounting it, I should be able to get through that situation. From what I read (and I can't be certain that those sources are correct) random stops don't include 1975 and older cars, and targeted stops are never going to include the Datsun 1200. You are absolutely right, though, by being non-compliant using an old body, I could get in trouble. That is certainly worth sharing with anyone reading this thread.

JohnC, You are absolutely right about cars (newer than 1967, I think) not being smog exempt; merely "exempt from biennial inspection if 1975 model year or older." I received your message a while ago and have read about everything you quoted. Please give some references, because I didn't find your list to be accurate (I really want to know, not disagree for disagreement's sake). I searched for each term carefully, including gov't websites, and to the best of my understanding: #1 and #2 don't apply to cars 1975 or older at all. The second part of #3 doesn't either... However, any police officer can pull me over at any time, and have me pop the hood and he/she can do a visual inspection on the spot. I did not find examples of them impounding 1975 or older cars, but citing them to be inspected. In my defense, I did write yesterday "SR20DET RWD is not a US engine, so every one that is in Calfornia is breaking the law." I'd suggest people follow the following article to avoid trouble: http://ericpetersautos.com/2011/06/13/classic-cars-and-the-smog-police/ In addition to what he says, I'd also paint/decorate your newer engine with classic Datsun colors and Datsun stickers. Also, if a citation instead of impound is the penalty (which I cannot absolutely verify) have the stock equipment or whole pre-smog engine ready to drop into the car. All that said, if I built this 1200/Miata... I could just use an L20B or build a Frankenstein LZ22 block with L20B head, forged pistons, porting and such, and that would pass a visual inspection, and I could get a more powerful engine later.

I just talked to a guy at Exomotive; he was friendly and knowledgeable. It sounds like if you (someone reading this thread) are interested in an autocross car to build, their complete sets are definitely worth considering. However, none of their equipment is designed such that I'd be able to use just part of it to attach to any car body. They also have their hands full and can't do any custom complete tube frames. However, he was kind enough to discuss it with me, and to explain a few things. Apparently even steering linkage issues are not a problem with Miatas and LS1 engines, so that's promising. The MEVX5 (except the ultra-light) really amounts to just a cosmetic rebody kit for a Miata, so it uses the Miata's entire structural body. So structurally it is not a redesign. The other designs really aren't conducive to being used under an existing body. Perhaps I can get them to sell me just bottom tube frames built on their jig, but that leaves a lot of custom fabrication left to do. Back to the drawing board... I dowloaded a bootleg FSM (factory service manual) for the Miata (low res, in German), and a free 1200 FSM (quality and in English). At first I was going to quote the exact dimensions here from the body geometry pages, but the thread will not benefit from it. After studying them for hours, I realize there's no replacement for going to the junkyard(s) tomorrow and actually measuring and knocking around on some Miatas, and see what they look like wrecked! From the manuals I have an idea of what I might do, but the junkyards will help me figure it out better.

Thanks again Socorob, twice! I tried to reply to you last night, but the forum would accept. That "Locost" idea is really cool: http://en.wikipedia.org/wiki/Locost There are several manufacturers and several donors, but of most interest are the ones that use the Miata as a donor. Some are shoddy and incomplete. But I looked at quite a few and am particularly fond of this one: http://exomotive.com/mevx5/ That would be just barely enough car for me, my dog, and a few groceries - so that's just what I want. It maintains the legal identity of the donor Miata, which if I can get sufficient CA approved performance upgrades, might actually work for me. I guess I have to consider this further. Besides that example, the Locosts are all too small and require a lot of jumping through hoops to get licensed in California. Building a smog exempt classic (even a tiny coupe like the 1200) still seems my best option to get what I want. In fact, I wrote to that company last night about bottom rails or a custom cage to fit inside a body. I'll let you know if that gets anywhere. They already have jigs prepped for most of it, and maybe I can buy their complete cage and then have it modified, from one of their models. Or perhaps another manufacturer will do it. I checked CA law very carefully; the pre-smog car (with full suspension/frame swap) would still be smog exempt and not require any inspection as far as the laws I could find. It would look like a Datsun, presumably use the engine of a Datsun, so would still be a Datsun. If I wanted to stay smog legal in what I build, I have to admit that Exotec's MEVX5 coupe which maintains the Miata's legal identity is extremely appealing. With a stated budget of $8K, that $7K body plus a donor and the work to put it together might put me well over $10K for just a running car, maybe $12K may be more realistic.

Holy Crap! Thanks again Socorob, a Google search for the Sunbeam Alpines (and other cars) using Miata subframes led me to a very helpful image. I don't readily see how to post it directly in this thread, so here's a link where it is the first image: http://forum.miata.net/vb/showthread.php?t=449226 (please PM instructions on how to post the image directly, and I'd edit this message accordingly) It is a beautiful photo of a complete Miata subframe set with the center (spline?) and complete drivetrain, sitting in a driveway like all you'd have to do is wire it up and throw on a saddle! Okay, maybe not, but to see that it is self supporting is very encouraging. The number of connection points (from prior knowledge) are very few. As the wheelbase is only 30mm longer than a Datsun 1200, and the track ~6" wider, the Datsun body should be relatively easy to modify to match (move front wheels forward 30cm and flare fenders at least 3". The Datsun 1200 would also be at the ride-height of a Miata, effectively lowering it substantially but with perfect suspension geometry! With this photo in mind, I'd be inclined to keep the entire 1200 besides the suspension, and a classic Datsun engine (with carburetor and minimal wiring necessary) for the initial build, with obvious upgrades of brake master cylinder, custom driveshaft, and a solution to the steering arm, to name the most obvious concerns. Unlike those perfect ground-up restorations, I'd be inclined to leave the car mostly "old." I think it would add to the charm of when the car flies around an autocross track, or spanks most high dollar sportscars from a light (at approximately 1/2 the weight, using a built SR20DET with aftermarket control and new turbo) though performance may be entirely satisfactory with an L20B. I was going to give a link to a finished project as proof, but did not find one yet. No matter, I know of at least one racing fabricator that uses Miata subframes to build their racecars.

socorob, Thanks for the info. I did come up with a plan that would avoid the nightmare: Take two cars worth nothing, but adequate for prototyping, and combine them. Get it to work (or not, and stop there) and potentially get another pair of donors to built it right. I happen to live near a relatively large supply of rust-free Datsuns (Sacramento Valley), and even better selection if I expand my search to all of southern California and Arizona, and tow something home. What do I mean? * Someone is selling a 240Z shell near me on Craigslist right now for $80 with minimal rust. I suppose it was a restoration that failed. So I'm sure I can find a Datsun 1200 shell or complete car that is no longer road-worthy but has a clean title and non-op registration (or "out of system" as it is called in California) for next to nothing if I'm patient. * I did a Craigslist search and found a huge selection of high mileage first generation Miatas under $1000 complete with just a blown engine. So I should be able to find one adequate for a floor and subframes (even if I have to replace the suspension & brakes when finished) for nothing or next to nothing - even if I have to wait to find one with... a salvage title, giant DMV back-fees, high mileage, blown engine, transmission problems, golf-club damage to the body, ripped top, smashed glass... in some way - complete junk. Yet as long as it is a roller that has a good floor and complete suspension, it would serve my purposes. * Then comes initial fabrication or prototyping. I need to find a welder willing to help as a hobby, or in trade, to just cut and tack-weld a roller. Maybe I even get the car mostly done and enroll in a welding class for fun, and use the stripped down car as my class project. (I happen to have extra time) Perhaps that roller works out beautifully so I continue to complete that project [or learning from mistakes, start over replacing whichever donor is junked] * strip it down, eliminate rust, seam weld where necessary, add doubler plates, primer, "home paint" everything the intended color during assembly, basic body work, etc. Mount whichever cheap engine is most convenient for prototyping (Datsun or Mazda). * Get it road-worthy and drive it. Works out all the bugs in body and suspension. Get it to look good enough that the CHP (highway patrol) isn't going to look at it sideways. Get it to the level of a road-safe old Miata, start driving it hard, and watch for any problems that pop up. [hopefully, the cost up to this point is quite minimal] * Only after it passes every test and is a sound vehicle, do the following in stages: ** Install a rollbar or rollcage, additional seam welding ** install an SR20DET with upgrades ** swap/rebuild/upgrade the Miata suspension and brakes ** build a worthy interior (racing seat, sound deadening, carpet or bedliner material, nice dash & gauges, door panels, headliner, cargo pad) ** pay a shop to paint it properly the same color used during initial assembly. **get it dyno tuned and get a performance shop involved to help sort out the car This seems like a plan to go about the project that I have outlined on this topic, and I hope this topic continues. [it appears this is a home project, not one to be outsourced out-of-country. I had to ask, right?] Any ideas or corrections on the above list, please elaborate. At this point, I may or may not build such a car, as I'm becoming increasingly convinced that I can get what I want within my price range by buying a sorted 240Z or 510 already swapped to a sufficient engine, and update the stock suspension to an adequate level (see video above), especially if it is time for the seller to pull the engine and rebuild it (so the price goes down, and I can put my money into a proper engine build, and refresh or improve any shortcomings), or buy a project that is only nearly complete but all the expensive swap parts are already purchased.

Well, I'm not sure why I'm still up... but I'll give a brief response. This was the first time I've considered outsourcing to Mexico. I figured since brute-force metalwork might be had cheaply there, I was curious about exploring it. I've found no backing on that plan. If it were the case, the mating of two large assemblies (body and floor) would be rather straightforward there, and not rocket science. A quality seam-welder can be found most anywhere. From your examples as to reason for a particular plan, I might say... the 350Z does better on the skidpad on the 240Z, and the combination described here could shave 1/3 of the weight of the 350Z - and then allow modifications to the engine that can only be done to a smog exempt body. Another answer is that while I'm not fond of Mazda in particular, I can't argue with their significant placement in national finals of SCCA SOLO II, and they are slightly larger than the Datsun 1200, so the floor (or a portion of the rear floor only) can most effectively replace the cheap live axle. The front subframe could be mounted 3cm forward of the stock 1200 subframe (on custom rails if needed), or the entire front and rear Miata subframes can be moved "forward" relative to the 1200 body, leaving the only interference possible with a particular Datsun engine remaining to be the steering linkage; and improving the weight bias. Also the Miata subframes (I have pictures, they can be found easily enough) are extremely self-contained. If they are mounted to an aluminum backbone and the Miata body is steel - that could be absolutely perfect. I just use/fabricate a steel floor that mates (perhaps bolts) to that backbone, and the rest can remain Datsun. Yes, my purpose is to skirt the law. But I'll be sure not to break the law, or at least stay within bounds that keep my car from being impounded. (SR20DET RWD is not a US engine, so every one that is in Calfornia is breaking the law). I'm pretty certain that suspension swaps and frame mods are not legislated. Perhaps oddly, I fully intend to use a high flow cat. I'm not looking to make a polluter, but a car that doesn't abide by their over-restrictive laws. A very quick Google search shows that your space pen idea is an urban legend. Pencil leads pose a hazard in zero gravity, and the Fisher company produced a solution with their own money ($1M-$2M depending on source) for Nitrogen charged sealed cartridge pens and sold them to NASA for $1.98 each, patenting them in 1965 and started selling them to NASA in 1967 (varies depending on your source). The Soviets started using such pens in 1969. http://www.scientificamerican.com/article.cfm?id=fact-or-fiction-nasa-spen http://www.snopes.com/business/genius/spacepen.asp http://en.wikipedia.org/wiki/Space_Pen http://mentalfloss.com/article/13103/russians-didnt-just-use-pencils-space http://io9.com/5838635/the-million-dollar-space-pen-hoax Why the references to such a trivial point? Fact check everything you write, or clarify with "I think, in my opinion, as far as I know, etc" http://www.truthorfiction.com/rumors/s/spacepen.htm#.UhM7n1Nr9dI All that said, I might simply purchase a 240Z or 510 already built and engine swapped, even if it needs additional work to complete or refresh. Goodnight.

Okay, you require evidence... As a hobby, I designed and hand built one old school high-compression Frankenstein 20R/22R/21R engine on the garage floor in 1988, back when TRD was actually a resource for hobbyists. That was for a 1975 Celica, which required octane boost. I drifted that car, back when there was no such term. Did several aftermarket mods to that car. Since then, I did several engine R&I's for myself and others, paying machine shops to do long blocks or buying JDM longblocks. Tranny swaps and all the usual repairs and aftermarket upgrades. Even specified some custom Ferrea valves. I even did an 1986 Honda Frankenstein in the 1990's that was unrecognizable to CA smog. In fact, it passed (and I quote) "Like a brand new car." I've also done some significant electrical repairs (on a theft-recovery). I've chopped cars up with Oxy-Acetylene, and am a proficient solderer, but that does not make me a welder. All I've done is use Naval Jelly (cleans my belly button right out!), sandblasting, and primering. Am I a novice? Intermediate? Whatever. I've just chosen to own about three cars at a time for many years (generally one sport, one grocery, one truck), buying them dead, fixing them up, and selling them (usually selling them in good working condition) when I move on to another project. As to Z cars, did you notice my tongue-in-cheek moniker I chose for myself? Three Dead Zs! I FAILED to do a ground-up strictly to stock restoration of my 240Z after having it as a back-burner project for several years, restoring many systems but finding some parts hard to find, had a matching parts car, and picked up a nightmare of a modified 1974.5 260Z (I think it was #12 built as a matter of trivia). I had a grocery getter and a cargo van at the same time, but I found it frustratingly humorous that I had three dead Z cars on my property. I chose the moniker as a way to poke fun at myself. So yes, I am quite familiar with the S30 design and also how good intentions can end in failure. The housing bubble "punctured" and I lost ~$200K, brought my cars with me to several rentals, and finally had to give them up for Ch 7 Bankruptcy. Now I'm back to being able to build one, but can't waste any money. I will have about $8K to devote to the initial build, and after a couple years could put a few thousand more into it. My library related to Z cars is second to none! So when I brought up this hybrid project, I am planning one that I can finish completely without crashing and burning yet again. Why choose the whole floor or subframe set of a newer car? For years up to the start of this thread, it seemed easier to support a complete car and chop the body off (leaving everything intact), picking up a S30 shell that has spent maybe a decade in an arid field (Sacramento valley is ideal for finding them), support the body so it doesn't warp, and lay the body onto the complete donor, with significant welding necessary, additional doubler plates, tube framing, plumbing, exhaust, order custom driveshaft if engine/transmission don't match the floor, and so forth. If consensus of this thread is correct, that's really not in my budget. It does seem like the Miata subframe set under a Datsun 1200, with a SR20DET would be a combination to research further. A little go-cart under 2000lbs, with autocross-worthy suspension, and an engine that can put out more power than I would want. Power to weight ratio of 1:8, where many races limit to 1:15? That would be quite the monster. For the S30, as I referenced in that video, it does seem that building the suspension and body to basically stock is entirely adequate. Swap kits exist for some really desirable engines (SR20DET, entire RB series, though I might choose something light with just enough power to suit me). I really want to avoid dealing with dual carbs or early fuel injection again, as I am in a unique location that one could drive from sea level to ~8000ft (haven't clocked it) in maybe an hour! Altitude compensation was a real issue with my cars. As someone mentioned (though the link was in Japanese, I knew the design) I might do better starting with a late L28ET, overbore (with sleeves?), and modern turbo with intercooler, ECU, and bolt-on equipment. Some of your questions are not pertinent, and a bit condescending; but I've tried to give an honest and humble answer to most of them. What's wrong with the stock layout? The S30 has bumpsteer and lift instead of downforce, but it and the Bluebird are pretty good but poor metal quality and may require significant restoration and reinforcement, the 1200 is a piece of crap but a very interesting shape and size to me. All of them might have hidden structural flaws after over 40 years - so the idea of using a modern system and effectively using just the shell and VIN# of the pre-smog car is very appealing. "Looking at wheel base is a little strange as well. Most cars don't come with a chassis anymore," You are completely wrong here. The wheelbase relative to the design geometry has a great deal to do with hop, brake hop, over/under-steer, roll center, ratio of lateral vs longitudinal weight transfer... and I was going to quote Herb Adams' Chassis Engineering. Too much bother. The manufacturer took wheelbase into account in their subframe designs. I know that the engineers that the manufacturers hired are better at their job than I am. Therefore I'd be inclined to use their design! Oh, and "no chassis anymore." Uh... what? Whether unibody, tube frame, or ladder frame like a truck - there's a chassis involved. Oh, and as to narrowing the track - absolutely not: use bodywork to match the donor suspension geometry, not the other way around. "If you use the running gear and any integral structure from the donor car, then it actually becomes a Z body kit on the donor car chassis, that's the reason almost all the cheap kit cars are registered as beetles or fiero's" YES IT DOES! I'd use just enough of the Datsun to barely satisfy the law, so they think it is a Datsun. Unlike a kit car, I'd title the Z car before modifying. That's the point. However, it seems this project (subframes or whole floor/firewall/dash/electronics) seems more appropriate to the Datsun 1200 (or 510 'goon) than a Z since the stock Z suspension can be adequately updated - I just wanted to have metal work done instead of the modifications required for an engine swap. Looks like a ordinary engine swap is the way to go for a Z or 510. "something that is misaligned and twitchy, or worse handles much worse than a prepped z chassis." That's why I'd preserve the donor's suspension geometry. "...driven a Z..." Yeah, I drove two of mine. Your opinions and advice are appreciated. I've laid out my responses to many points not just for your sake or mine, but because this is a public forum. It may be (and I have a heck of a lot of research to even suppose this) that I can manage to use Miata components (and exact geometry) to turn a Datsun 1200 into a monster autocross-type car. (The suspension swap would put me in an open class, where I'd be up against supercars, so I wouldn't win any trophies - I never set out to "win" but to have a car that is a blast to drive)

Space Shuttle Tile underbodies! I like it! Perhaps motive will help context for looking for such solutions: * California SMOG law does not allow any performance modifications, so using exempt bodies is the only way around it * High performance modern cars cost a hell of a lot, and tend to weigh 3500lbs or more with bloat * Modern cars that can be afforded lose value at an incredible rate, classics tend to maintain their value * Some late model performance cars have better cG, skidpad, downforce, electronics, drag coefficients, than can readily be achieved on a classic * Some late model cars have dual wishbone, reliable, light suspension systems * Most late model cars that are RWD are also bloated luxury cars. * Most late model cars don't really allow for home mechanics - owners aren't even expected to change their own spark plugs anymore. Maybe what I set out to do (weld a different floor, etc) is not available. I accept that possibility. Or maybe it is, and still seemed worth discussing. I did find a video that shows a well built 240Z with RB26DET that was superior to a high-dollar modified 370Z in autocross, tested by MotorTrend: That certainly says that for autocross exclusively, stick to the 240Z as designed, with some updates. Having a limited budget, being stuck with California's smog laws, so not able to heavily modifiy a newer car (and not being able to register it if some obscure flaw makes it not pass smog); I'm inclined to heavily modify a classic. How to do it is still open to consideration.

I was notified once Peej410 wrote his response, and spent the entire time since doing research. I split my response into two (the direct response is above). So I'm did a little homework here...(assuming I find accurate sources) On Datsuns.com, 240Z-280Z: Track (F/R): 53.3 / 53.0 BMW E36 M3 (from a forum quoting a sales brochure) Track (F/R): 56.0 / 56.6 Lexus IS300 AutomobileMag Track (F/R): 58.9 / 58.5 Wheelbase: 240Z-280Z: 90.7 (102.6 for 2+2 model) BMW E36 M3 (Wiki): 106.3 IS300 - 105.1 I'm also have a copy of SCCA's SOLO II autocross 2012 finals open. (Available, I can probably find a link to download it) I'm a little perplexed. As verified by the above document, I knew that the BMW M3 is excellent at autocross but it's narrow track vs long wheelbase is counter-intuitive. Of course not one Lexus placed. A large number of 240Z's and a 510 (I have to assume their suspensions are basically upgraded from stock, following SCCA rules) placed in last year's finals. The BMW subframe swap sounds great... but not after I compare to restoring and upgrading the stock 240Z suspension, when autocross (not competition but style of driving) is my primary goal. Especially when compared dollar for dollar? Miata's are significant winners in SCCA SOLO II, and I'd use any body that happens to be a perfect match. The Datsun 1200 is quite close, with substantially less weight. It seems the ideal combination when autocross is considered (combined with the fact that I'm under California's SMOG laws), and I want an enclosed hatchback (I admit, that is merely for my giant dog). Even if SCCA would bump me to a class I can't possibly win, it is the feel of the car that I'm interested in achieving. "Hill climb 260Z Frame" Sure, I love that 4WD V8 car. That is an excellent car for it's purpose, but my purpose is a daily driver / autocross car with a goal of 25% weight per corner, RWD, using late model technology. Do you have any source of information for the frame design and what suspension is used? I wouldn't want a Chevy S10 frame, as some source says it has, but if it has a custom ladder frame or backbone with information available, please share!