Michael

Nice build! Granted that it's too late to presently matter, but have you considered setting the firewall back, to create more room in the engine-bay, and to set the engine even further back? Given the plethora of fabrication-skills that we see on the Forum, I'm surprised that this modification isn't more common.

As tube80z pointed out, technology incessantly advances. Parts that were formerly experimental and custom become mainstream, and eventually available for sharp discount on the used-market. Donor-cars that were formerly prized and expensive, become junkyard finds. When some of us first dabbled in this whole V8 Datsun thing, the LS-series was brand new, and the aftermarket was first getting around to supply aluminum heads for the first-generation Chevy V8. The first decision to make, is whether the car is even worth keeping. Rust? General condition? Does it drive well? Imagine the same car, but with tighter suspension and maybe twice the horsepower. Would that make a huge difference? If so, proceed. If not, not. What sort of bodywork is required? Is it only cosmetic, or is structural remediation necessary? Assuming that the body is in good shape, I'd proceed with suspension and brakes. Avoid the temptation for ambitious upgrades... keep things mild. The FAQ on this Forum is invaluable! Make small, incremental changes... and keep driving the car. Minimize time spent on jackstands! That way, if anything goes awry, or not to your liking, it could be reversed... or the car could be sold, at minimal loss. Oh, and please post photographs. We want to see what this thing looks like!

Post a photograph of the engine compartment. From this we can discern whether the original swap was the "JTR method" or the less advantageous non-setback one. If there's rust in the floorboards, almost certainly there is rust elsewhere, in nontrivial amounts. This may or may not require immediate attention, but it does merit jacking up the car (suitably supporting it!) and a thorough examination. Some rust, while annoying, is only cosmetic. This particular car evidently has a 5-lug rear conversion. Does it also have a solid rear-axle conversion? Such a conversion remains controversial even to this day... but properly done, it has its own appeal. What is the rear-axle ratio? If the transmission is a TH350, it won't have an overdrive gear, which is annoying on the highway. Lack of overdrive is, in my opinion, the main reason for why a "race car" is unpalatable on the street.... something to consider. Otherwise the standard routine is to examine and possibly refresh the engine. Do you have specs on the cam? The heads? The compression ratio? Have you done a compression-test? The standard tuning-approach applies, whether it's a Datsun or a Chevelle... lots of literature on that. BTW congratulations on the purchase! Aesthetically it looks aggressive, without being outright garish. Those fender-flairs nicely split the difference between too-much and not-enough. But I do wonder about the rear axle... the rear wheels aren't particularly wide, yet they protrude considerably outboard. Perhaps the axle is too wide? Could it be narrowed? 4-link or ladder-bar or something else?

There is, if memory serves, a JTR book for the S10, just as there is for the Datsun Z. It presumably has the relevant information.

Another issue is the primacy of class-rules. Some very intuitively appealing things - by my reckoning - may run afoul of class rules. One example is the business with the total included-angles in the main hoop. Must be < 180 deg? Consult the rule book. And on a similar subject: can the hoop be welded to the surrounding sheet-metal? If so, this ought to be of particular value in alleviating the aforementioned C-pillar stress concentration. We should probably move this thread to the brakes/suspension/chassis sub-forum.... mods???

Welcome "back", Katman! For many of us, the problem is ostensibly a simple one.... after many years of hibernation or at most sporadic use, the Z finally gets a chance to stretch its legs. The engine runs, more or less. Things creak in the suspension, but it suspends, more or less. Even the headlights work. And the brakes? They worked in the driveway. Finally getting the car up to speed on the local rural road, I press the brakes, and... mush. I pump them, and yes, they sort-of work... but the car pulls hard to the left. One can feel a set of brakes (front left? rear right?) lock up and smoke... while another set feels like somebody greased the pad with bacon-fat. Then comes the question: what should I do? Those pads, remember, haven't been changed since the 1990s. Maybe even the 1980s. Do the calipers even work? The brake fluid is older than some of the members on this forum. So... should get refurbished stock parts from Autozone, bleed the brakes, and call it good? Maybe I should. That would be the economical thing to do. But for many people, it feels deficient, inadequate, simplistic. Technology has moved on! Progress!! And I should install parts that were already so-so almost 50 years ago??? Thus, the quandary. It's not about racetrack performance. It's about personal psychology.

The thread cited in CalZ's post is indeed immensely helpful. Unfortunately, the principal link with photographs, http://s160.beta.photobucket.com/user/psanders240/library/BSR-260Z-IMSA, is now broken. The thread hasn't been updated in 3 years, since its main contributor (JohnC) died. The original thread is from 9 years ago. My own subjective belief is that the attempt to structurally strengthen the Z, while admirable and maybe eventually necessary, tends to derail (no pun intended) swap projects. Do the swap first, and get it running, even if the chassis is floppy and inappropriate for the aggressive amount of power. Also be mindful, as JohnC used to frequently observe, that suspension-loads are higher than drivetrain-loads. That is, chassis flex is a greater problem for a stock-powered Z driven in a racing situation, with stiff springs and aggressive turns, than in a Z with quadruple the power driven on the street (or in drag racing) with unmodified suspension. Also, if doing an aggressive engine/transmission/differential upgrade, almost invariably there will be metal cut, new metal welded and so forth. This means new points through which loads are passed. It also may mean that "conventional" approaches at strengthening the chassis can interfere with the swap-related mods. An example is the venerable "Ron Tyler differential mount", which was for the R200. Would it work for the R230? Probably not in "stock" form. So... fit the engine, do the swap, get it running, and THEN worry about alleviating chassis-flex. I speak from experience, because I did this backwards, worrying about the structure first. Yeah, it's rigid etc. And?... project has taken 20 years.

If the objective is to reduce noise without introducing undue restrictions, a dual-exhaust (with proper crossover) is the better solution, provided that there's enough room to accommodate mufflers of sufficient capacity. The venerable David Vizzard has an excellent discussion on the topic, in his "how to build horsepower" books. One pitfall that's affected many of us, is that mufflers from the muscle-car-oriented aftermarket exhaust purveyors tend to be loud. One gathers that this is more for style than outright performance. Google-search reveals some options. One example is http://myshinycar.com/quietest-mufflers-market-v8-3inch-mufflers/ . This is more of a puff-piece than an objective article, but even so, its various links are worthy of consideration. There is on this site a plethora of threads journalizing member's cars' exhaust layout, but to my knowledge there has not been any systematic acoustic test.

With a ZZ4 crate-engine (in the "JTR" position, or the "Scarab" position???) it is unlikely that the swap itself introduced a significant departure from stock weight distribution... some weight gain, yes,... but this should result in a more even settling of the car on its springs. If the back-end is significantly lower than the front, the likely culprits are (1) aftermarket tinkering, or (2) something really worn/damaged in the suspension. If the car is cosmetically pretty, structurally sound and gets fantastic acceleration, there's ample reason to tear into the suspension, to give the car the vitality of suspension that it deserves! So, the suggestion is to pull the rear (and eventually the front) struts, and perform the standard regimen of refreshment... new springs, new bushings, new shocks. This would also be a good time consider the intended use of the car... street driving, drag racing, road-racing, etc. The principal use would inform the choices for suspension-parts... lots of suggestions over in the suspension forum. And congratulations on a good-looking, hard-accelerating car!

One gathers, at least anecdotally, that for a well-flowing modern aluminum radiator, fan-requirements (CFM across a given pressure-drop) are surprisingly low. The above-cited fan supposedly flows 3000 CFM, but across what pressure-drop? And at what oncoming flow speed (basically the driving-speed of the car)? The reason for my skepticism is that the label purports that the fan only draws 80 Watts. That's not even 7 amps. But if it works, it works. Back in the proverbial good-old-days, the default solution was the "universal fit" Flex-a-Lite "Black Magic" fan; something like this: https://www.summitracing.com/parts/flx-168?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-flex-a-lite&gclid=Cj0KCQjw7YblBRDFARIsAKkK-dIQeVohN8W2bXWd_eUn3Zd_7oQ4kn7sadbhZGekgV3KwmX1bVOABAgaAgnPEALw_wcB . It has about the same CFM and similar physical size, but is listed as drawing 19.5 amps (234 Watts). I can report good results with that fan, on a large-ish Griffin two-row aluminum radiator.

Welcome back! What happened to the big-block car? Sold? Still running? This is the first time that I've seen a 5.3 short-block. To my neophyte eye, it looks like a superb candidate for some very aggressive overboring... like +0.100. Unfortunately, even a cursory internet search reveals that the 5.3 is evidently not friendly to large overbores. Oh well. Strange, isn't it, that there's such surfeit of 5.3s, but relatively fewer LS-series engines of larger displacement? I wonder why that is.

Let me try with another analogy. Toyota has in recent years been campaigning a NASCAR "Camry". It's a beautiful machine! As with all NASCAR entrants, it has tube-chassis and RWD and a big pushrod V8. And so forth. I'd love to buy one, and yes, drive it on the street - registered as an, ahem, Camry. That's the direction that I'd like to go with a Z. Why then even tangle with a Z at all? Emotional connection, decades spent on it, personal feels of one or another kind, and the opportunity to register a maximum-effort track-only race car as a supposed street car. My locale in principle allows that - well, maybe not, but it may still be possible without outright committing a crime. At the very least there is no smog-check or equipment-inspection.

Harsh crowd here! Having spent 20+ years tinkering with my Datsun, having it be my garage companion through several human relationships and countless too-human failures and foibles, I'm sentimentally attached to the machine. But it's not what I really want. It's my companion, yes - but not my dream. And this thread asked about dreams. The dream would be a truly iconic racing-car, that redefines the possibility of what's possible in vehicle-engineering. Short of that, the mini-dream would still be a foray and achievement far beyond anything that I've been able to do, or might ever likely be able to do. Thus, again, the term "dream". As to reacquainting ourselves with hardnosed realism, the "dream" is to merely sort out and to render reliable what I've already tried to do. The engine that I have currently installed has "potential" for some 500 hp (it is after all 461 cubic inches, with some top-shelf parts is semi-semblance of good order), though I doubt that it actually produces half as much. The brakes... occasionally work. The car is squirrelly, ill-tempered, rough, more of a white-knuckle facsimile of amusement than anything serious on the road. I dream of fixing that someday.

* Full chromoly tube chassis (custom designed, verified with extensive finite-elements modeling) * Unequal A-arm suspension on all four corners, based on some blend between Miata and 5th/6th-gen Corvette (with suitable design and testing) * Carbon-fiber body panels affixed to tube chassis, after proper wind-tunnel development * LS7 (Chevy 4th-gen SBC) engine, twin turbo * TBD gearbox * Ford 9" differential and center-section, with suitable half-shafts and inboard brakes * Lexan windshield etc. * VIN from 1970 Datsun Z welded into firewall In other words, the only Datsun part of the car would be registration as a Datsun. It wouldn't even attempt to resemble at Datsun in its external lines, let alone internal components. Why not? Because there are too many compromises in building a "dream car" from the initial canvas. It's taken me 20+ years to figure that out.

Miata.net itself admits that its search-function is subpar. Recommendation from the more venerable members there, is to search for a topic via Google, thereby finding the right Miata.net thread. For purposes of troubleshooting or getting advice on repairs or minor upgrades, it's fantastic. For things like V8 swaps into Miatas, the utility of the site is more suggestive than explicit. Then there's miataturbo.net. Rather sophomoric and dismissive attitude by veterans towards newbies, but the intent is noble: they're trying to keep the site technical and useful for rigorous instruction, rather than water-cooler blather. Much of their content leans toward electronics and tuning... probably of use to the turbo and fuel-injection-oriented people on HybridZ. And yes, that Manta is spectacular!

This looks like a novelty. Based on the physical size and the gear ratios, it looks to be a direct competitor to the G-Force revision of the venerable T5 (https://www.gforcetransmissions.com/tran_gt-5.asp)... prices are similar. The G-Force version appears to have slightly higher torque/hp capacity. Let is know what you think of it!

And now, 19. Canadian drinking age, eh?

It’s interesting that you mention Miata.net. I’ve been active on that site, for a decade or so, but mostly from the viewpoint of stock or lightly modified Miatas. Miatas are lovely cars to drive, but noxiously difficult for V8 conversions, requiring very substantial re-engineering for even a stock LS1 (or similar) V8. The S30 Z requires so much refurbishment and sorting-out just to be livable on a daily basis, but the cavernous engine-bay is unrivaled as recipient for a large engine. Miata.net doesn’t have the level of FAQ as does HybridZ. There is no equivalent to the wind tunnel campaign that was done for the S30 back in 2007. There are no legendary members like JohnC, whose posts have come to be pillars of received wisdom. And there’s surfeit of dumb “newbie” posts about generic and trivial things. But Miata.net remains lively because of persons to whom it appeals: middle-aged men who remember when the NA Miata came out in 1989, who couldn’t afford it then, or for whom family/career/etc. interfered, and who now have the time and the garage-space to tinker. Without making a swipe at our younger brethren, it seems to me that for whatever reason, Z’s tend to appeal to people who are less established in life, less-experienced, who have more eagerness and dreams than wherewithal or practice. So, the questions tend to be both ambitious and naïve… which is irritating to the veterans. If somebody asks why his 1991 Miata is running roughly, it’s a quick deduction that the catalytic converter has clogged, suffocating the engine; or the plug wires, notorious for going bad, have indeed gone bad. If somebody asks what’s the best way to swap a Hellcat V8 into a 1971 Datsun, and will the rear-end be strong enough, well, that’s a much more irritating question, is it not? Also, it seems that for whatever reason, the originals/regulars on HybridZ have gone silent. Some have passed away. But others I’m sure are not only very much alive, but still own their Datsuns. What happened? What happened for example to “Katman”, to Terry Oxondale, Pete Paraska, Mike Kelly, Denny411 and so forth? On Miata.net, we have numerous people with 20K or 30K posts, who have owned a dozen Miatas over the years, who have been buying and selling, driving and storing, modifying and preserving them for nearly 30 years. Why has the same trend not persisted with HybridZ? Also, there are modern questions on perennial stalwart topics. For example: “Suppose that I’m happy with stock brake-power, with maybe performance pads and SS lines. But I want lighter brakes, for less unsprung mass. And I don’t want to deal with drum brakes. I don’t want to rifle through junk-yards. I don’t need or want 13” rotors or 6-piston calipers. I called Wilwood and Arizona Z-car, and that’s all that they had. What else can I do, now, in 2019”. Or: “So, you guys tested a bunch of Datsuns in a wind tunnel in North Carolina with no moving ground-belt, no boundary layer sucker and some high blockage. My university has a high quality wind tunnel with a moving belt and capacity to spin the wheels using embedded electric motors. With have a 6-component internal force balance and a particle image velocimetry system for getting time-resolved 3D measurements of the flowfield behind the rear hatch. What should I be thinking in terms of a test matrix?” Or: “My engine makes 650 ft-lbs of torque. I want a manual transmission with overdrive, but don’t want to deal with the weight of a T56. I need a blowproof bellhousing because I sectioned my firewall for 10” of setback beyond the JTR method, and my race-sanctioning body wont certify my car unless they see that SFI sticker. I called G-Force, and they told me that at my power levels, it’s either a T56 or bust. And everyone at my track insists that I install a Powerglide… but I want a proper manual transmission, with overdrive. What should I do?”

Don't do this. Have patience, and spend more money (if necessary, vastly more money!) on a car with fewer problems. Otherwise you'll spend 5 years doing rust-repairs, 5 more years doing structural reinforcement, and 5 more years nursing your wounds after you realize in year 11 that new rust has already formed where you had replaced the old. Alternatively - and it sorely pains me to say this - look for a less rare, less rust-prone vehicle of comparable low weight... such as a Mazda Miata.

Facebook is one of those newfangled enterprises that's completely passed me by. That forum traffic is falling because of the alternative of Facebook would be surprising... but only because I'm ignorant of Facebook. A related problem occurred at our local BMW enthusiast meetup, "Ohio Bimmers". Because it's more local, it's more conducive to semi-regular meeting in person. I would host "wrenching sessions" at my house, with some 5-10 participants in a typical gathering. Well, these were a common occurrence 10 years ago. They've since petered out. The culprit is demographics. Most of the participants were younger fellows, typically freshly out of college, age 23-26. In the ensuing years, they've done the Big 3: gotten married, had kids, and bought a house. The Big 3 are enormous drains on one's time, one's spare energy and one's capacity to engage in hobbies, be it modifying Datsuns or playing chess or going mountain-climbing, Perhaps in another decade or two, once the kids are grown and in college, the former participants will return. Meanwhile, some of the founding members of this site were around age 35 in the year 2000. Today they're in their mid-late 50s... seemingly the ideal time to reengage in hobbies. And yet, most are absent. Have they moved on to other cars? Have they burned out? Some, I know, went through divorces... then recovered and remarried. Others... who knows?

And that's golden advice right there! The JTR book itself exhorts readers to be sparing and parsimonious in their ambitions. Do a swap, not a "restomod"! Is the recipient-Z in good shape? If not, the swap will be unsuccessful, or at least a protracted effort. If yes, then there's a 25-year-old recipe for getting it done. The only thing that 's not thoroughly documented (still!) is the clutch hydraulics for the T5... throwout bearing, flywheel and pressure-plate and so forth. That's the only part that involves a modicum of improvisation. But here's the thing... you do the swap. You get it hooked up, bolted up, connected, buttoned up. Congratulations! Now you have a hot-rod. That hot rod requires tuning! Can you tune the ignition, the carburetor, and so forth? Do you understand port vacuum and manifold vacuum, proper spark advance, and so forth? That is the difference between a strongly-running car, and a turd. That is something with which you'll need to wrestle, whether or not you swapped the engine into a 240Z, or bought a Chevelle or Nova or whatnot with that engine native. And that's the art/science that's been waning and vitiating over the years.

Mpg depends largely on engine management: carburetor vs. fuel injection, camshaft profile and so forth. 20 mpg should be readily attainable even with a more aggressive engine build. However, truly high efficiency, in the sense of a modern sports car, will be hard to attain - even with the 240Z's weight advantages. The reason is lousy drag coefficient... the bane of good highway mileage. To answer your questions: 1. Do as little as possible, at least initially! Complete the swap, get the engine running and the car sorted out. Engine mods can come later. 2. This is entirely subjective and situational. So enterprising drag-racers are pushing 500-700 hp (or more!) without molesting the "stock" look. 3. Never, ever ever install a non-overdrive transmission in a "daily driver" Z! Your application is screaming for a T5. 4. Initially, do nothing. Between your relatively weak stock 350 and the stock wheels/tires, the R180 differential in your 240Z should be adequate. Later you can swap in the much stronger R200. Search the "drivetrain FAQ" for model years/varieties from which to swap the R200. The #1 discriminator between failure and success, is the condition of the Z that's about to become the swap candidate. Rust? Overall condition? How is the suspension? The brakes? Do things work in general? Are bits falling off? Rubber? Plastic? Doors close properly? Dents/body damage? Electrical systems? You're about to do an engine swap. Don't also make it a restoration. The #2 discriminator is falling into the "while I'm at it" malaise. Do as little as possible! Laziness is always its own reward, but sometimes it's also this best route to quick and definitive success. This is one such instance. Be strategically lazy!

Perusing the data from that 2007 wind tunnel test, I'm baffled by the results for the Pantera hatch. Intuition suggests that flow is already separated near the front lip of the stock hatch, and then continues as a set of oscillated separated rollers. This is because the stock hatch angle was poorly chosen. It’s too steep (pressure gradient too high) for attached flow, yet less efficient than a blunt (high angle), abrupt rear element… such as for example the back of a VW Rabbit. The rationale for Pantera hatch is to get up on attached flow, instead taking the pressure-drag penalty on the rear windscreen, but hopefully getting flow reattachment further downstream over the hatch. It is possible that this latter phenomenon wasn’t achieved in the wind tunnel test. I’m not criticizing the wind tunnel test, but am pointing out that (1) the result was counterintuitive, (2) the drag increase from the Pantera hatch was still small, compared to the unrelated issue of what’s done at the radiator/nose/airdam, and (3) design-variations on the Pantera hatch are still possible, which may actually reduce drag, instead of increasing it. By my reckoning, the benefit of a Pantera-style hatch isn’t a “hatch” at all, but a fixed lid over the trunk-area, merging into a fixed rear glass (or plexiglass). The benefit is (1) save weight, and (2) isolate the cabin from the fuel-cell and battery (assuming a trunk-mounted battery). If there is aerodynamic benefit, then that’s a bonus, rather than a main objective.

These are both factors. The intentional push to make this site more of an archive and repository for knowledge, than a discussion-venue, has cast something of a pall on freewheeling banter. Too much clutter of course obscures the useful information; the idea behind this site has considerable merit. But it's not without adverse consequences. I'm finding that so many methods that were revolutionary in 2000, are now mundane, or even obsolete. Suppliers have changed. Technology has moved on. As our cars age and become rarer, the emphasis shifts from engine-swaps to rust-abatement and restoration. "Parts cars" have all but disappeared. Instead of swapping damaged or inferior parts, the emphasis now is on improving what's at hand. Soon it will be time to post another Happy Birthday message to this site; it's about to turn 19! I miss the bygone years of intense activity, even if indeed most ideas have already been covered, and new discussion is not always warranted.

I have two data points, for both of which the evidence is scant and only qualitative: a 1972 240Z, and a 1978 280Z. I partially gutted the doors of my 280Z, removing the longitudinal crossmember and a good portion of the inner-wall sheet metal. I placed the detritus from both doors in a cardboard box, and weighed the box. It was, if memory serves, 10-12 pounds. The 240Z door shell-material may be lighter gauge, but the architectural difference between the two sets of doors is worth only 5-6 pounds per door... if that. My original 240 ended up getting sawz-alled (is that a verb?). I was shocked by the thinness of the sheet metal... but wasn't sufficiently engaged to measure it with calipers. Before cutting the tub apart, I used vice-grips to pry apart, peal back and cut chunks of sheet metal. Later, I did the same for the front bumper supports on my 280. The qualitative difference in sheet metal gauge was... significant. My casual hypothesis is that the preponderance of the weight difference in going from 1970 to 1978 is in the gauge of the sheet-metal, rather than the engineering of the tub (bumper supports, radiator supports, A-pillars, subframe "connectors", etc.). To Grannyknot's point...since your 280 tub is on the rotisserie, would it be possible to weigh it? Bathroom scales are notoriously inaccurate, but at least it's something... they have typically a 300 lb limit. Perhaps one scale could be put at each end of the rotisserie? Or would that damage the scales? My stripped 1978 280Z - with a fairly elaborate roll cage, a 454 big block Chevy and a Doug Nash 5-speed, weighed 2720 lbs, on 4 Longacre scales. This was with, at the time, cast-iron heads, most stock sheet-metal intact, stock hood etc. Since then, I've replace heads/water pump/etc. with aluminum, and have removed quite a bit of metal, undercoating and other bits. Hood is now fiberglass (homebrew design).