Michael

"The Z is meant to rev" ... well, this is precisely why I'm disillusioned with stock cars, especially in modern times. Anything that's reasonably light and nimble is saddled with an engine that's "meant to rev". But if you want an engine that's "meant to pull" - you end up with a pickup truck. I drove 4.6L Mustangs several times. At least from my perspective, these are not legitimate V8 cars, in the traditional low-end-grunt sense. To get decent acceleration, these OHC engines have to be revved, too! My Z ran only briefly, a little over 5 years ago, before the cam got wiped. i didn't have a tachometer, didn't have appropriate tires, and probably never got over 40 mph or 2000 rpm in that car. Nevertheless, it was breathtaking how it would pull nicely from a stoplight just by letting out the clutch, without so much as even touching the gas pedal!

For some reason the Japanese have a cultural inhibition against V8's and large-displacement engines in general. Yes, I'm aware of their displacement tax. But somehow a high-strung turbocharged inline-6 is OK, whereas an easy-going V8 is taboo. Fortunately at least the Germans (well, at least Mercedes) are starting to turn around, with some decent-displacement V8's. I'd love to see a large-displacement, low-winding N/A V8... in something weighing under 4000 lbs!

Dr hunt - about that 454 with Brodix heads... where those the Race-Rite heads, by any chance? I just purchased a set, with CNC chambers. They do require a little bit of blending on the intake side, but otherwise look pretty sharp. You mentioned "mild cam" - was that a flat-tappet hydraulic? Very notionally, I'm hoping to improve on the torque and hp numbers which you mentioned by going to a moderately aggressive mechanical roller.

L28et is absolutely correct - the search function suffers from a tremendous gulf between theory and practice. In theory, typing in a few keywords will reveal the sought-for list of posts. In practice, the number of false hits is overwhelming, the number of relevant posts that get missed is also large, and if you're such a newbie that you don't even know what keywords to use, then you're completely out of luck. I keep a folder of what I consider to be the more lucid of my own posts. Whenever I come across a new thread about big blocks, roll cages, aerodynamics and other areas where I feel that I have something worthy to contribute, I open my folder of posts, and cut and paste to quickly write a new post. That obviates the desire to insult the newbie with "go and search, you worthless lazy dweeb", and saves time in composing a new post. We're definitely moving in the right direction with the FAQ. I think that the best solution is to keep expanding the FAQ, and thoroughly warn all new members to first consult the FAQ.

You can easily do a basic V8 swap into a 240/260/280Z in decent condition within 120 manhours - if this is your SECOND swap!!! If you already know exactly what to do, you can do the job quickly. If you're learning and scratching your head and going down blind alleys, 120 hours is impossible. My swap has been ongoing for 6 years - and this is with a relatively stock suspension, almost no rust repair, copious amounts of professional help with welding (there isn't a single weld in my car that I did myself - because I can't weld!), no kids, plenty of budget, a very understanding wife, and an empty 4-car garage.

Doesn't anybody buy anything retail anymore? Go to http://www.jagsthatrun.com/Pages/Datsun_Z_V-8.html and order the book. It's like $35 - less than 1% of the cost of a VERY cheap swap, and 0.1% of the cost of a nice swap.

Now to do the JTR conversion...

I have to commend you guys - you're doing it the RIGHT way; build the engine, get the combo running, then worry about the cage etc. The alternative - to first build the cage, subframe connectors, and so forth - will inevitably run into finding rust, trying to excise the rust, ripping out the interior to create working space for welding (and to chase down more rust!), and parking the car for years.

Gabe beat me to it, so just to elaborate… use the “engineering form†(as opposed to the chemistry form) of the ideal gas law, P = rho*R*T, where rho is density. In S.I. units, the UNIVERAL gas constant is R = 287 J/(kg*K). So, rho = P/(R*T) = 8*(101325 N/m^2)/(287J/(kg*K) * 600K). The 101325 N/M^2, or 101325 Pa, is atmospheric pressure at STP. Units cancel to give kg/m^3, and the numerical answer is 4.707 kg/m^3.

The gearing issue will be important down the line, but I wouldn’t make it a priority while you’re still trying to install the motor. Once the motor is installed and the driveline connected, and that mythical first drive is under your belt, you may find that your original specs for the motor will undergo considerable changes. As the power band and other specs change, so will the ideal gear ratio. My combo also has a non-overdrive transmission, though it’s a stick-shift (Doug Nash 5-speed, with 1:1 5th). This was a good choice 6 years ago, because aftermarket blowproof bellhousings for the T56 were not available, and beefed-up T5’s weren’t around. I could have used a Tremec or a Richmond 6-speed, but the 6th gear in the Richmond unit is reputedly quite week, while the Tremec has a very notchy shift mechanism. Besides, I got a good deal on a used Doug Nash unit ($750 with the shifter). At some point I might do a rear end swap, with for example a numerically lower-ratio R230. The TH400 might be a tight fit in the transmission tunnel. Are you open to cutting up the sheet metal and welding in patches? Now here’s a question for the broader community: why is it such a common concern, especially for new members to say that they’ve got their bodywork and frame sorted out, their engine selected or in some cases already assembled, and even the transmission done,… but they’re worried about the rear end? I say, build the engine, build the car, take it to the track, and if your 60-ft times are disappointing or the rear-end grenades, THEN worry about replacing it! Broken stock parts are easy to replace. Fabbing new custom parts is what’s difficult!

Oh, this thread brings back the memories! But the sad truth is that very little has changed with my car since 4 years ago. The engine is still out and apart, though finally I bought cylinder heads and will mock-assemble everything (to check for clearances) in the next 2-4 months. I hope to finish the engine in the Spring of 2006, and maybe get the car running the following year. Grumpy - did you ever build that Z with the 454? And while we're on the subject of BBC Z's - whatever happened to Ron Jones and Brad Barkley?

Today I took delivery of Brodix Race-Rite oval-port aluminum heads for my big block Chevy. The heads were milled to 110cc (need to check to make sure), with CNC combustion chambers and springs for a mechanical-roller (245 seat, 580 open). On my 461 (0.030â€-over 454, otherwise basically stock shortblock) I hope to reach the “magic†500 hp at or below 6000 rpm, with a torque peak of something like 550 ft-lb at around 4000 rpm. Perhaps. The exact numbers aren’t important, but they are nominal goals. Other parts include Isky Red-Zone lifters and a SA Gear adjustable roller timing set. The cam gear can be rotated to give +- 6 degrees (retard or advance). I also got the Comp Cams steel roller rockers. Still undecided on whether to get a fancy multi-piece timing cover. And still undecided about the cam; it’s probably be from Cam Motion, which Pete Paraska recommended a year or two ago (yup, it’s been that long!). The heads came from a protracted, agonized decision-making process. I REALLY wanted to buy the AFR oval-port heads, but AFR still has no plans to bring them to market, despite advertising them on their web site. The next smallest-port alternative from AFR, 305cc rectangular-port heads, is doable but probably offers no midrange advantage on a 461 over the Brodix heads, and might even have a low-end disadvantage. If I were smart and bought a forged 4.25†crank, decent rods and higher-compression forged pistons, the performance envelope of my engine would have shifted enough that the 305cc AFRs would have made more sense. But as it is, the Brodix heads should do fine; they are reputed to outflow any heads of comparable port volume (and hopefully comparable port cross-sectional area!), at least on the intake side. The exhaust side could use some help. The Brodix heads are reasonably well-built. There are minor imperfections where the machined areas meet the raw casting, but that’s to be expected. Next on the menu is trial assembly to check for some tolerances, then ordering the cam and a checking-pushrod to check for more tolerances, and finally the custom-length pushrods (block was decked).

What makes the V8 swap complicated isn't the swap itself, but the various improvements, hop-ups and "while I'm at it" modifications. To begin with, most people have a Z with a significant amount of rust. I'd say that >50% of the swaps which get mired into multi-year marathons ended up that way because of body work. Second, in an effort to build a competative street/strip car - rather than a mere street car for personal enjoyment and non-competative recreation - many people try to push the technology envelope. And third, there are indeed flavors of the V8 swap, such as using fuel injection or an unconventional engine, which turn the project from modest to very complex. If this is your first "hot rod"-type vehicle, the best strategy - and I'm speaking from 20/20 hindsight - is to follow essentially what JTR recommends; buy a mid-priced 240/260/280, buy a 1970's full-sized sedan with a 350 and an automatic, and mate the drivetrain of the latter with the chassis of the former. Don't worry about the rear end for now. And don't worry about the 300 hp. In the long run, it will be cheaper to install a 180 hp smog motor, get the car running, and later swap to a hot small block.

If you have a non-overdrive transmission with a torquey engine, a 3.15 (or numerically smaller) gearset is very useful. For example, in my application (454 BBC with 6000rpm redline, Doug Nash 5-speed with 1:1 5th gear, 3.54 R200, 24â€-tall tires) gives a max allowable speed of 121 mph. With the right tires and suspension setup, that will hopefully not be too far from my expected 1/4-mile top speed. So no problems there. But, cruising at 70 mph gives 3470 rpm – and that’s a little too high for comfort. Even a 3.15 is numerically too high, considering that first gear is 3.27:1, and it’s a big block. Something like a 2.7 rear would be even better.

Gen I SBC and Mark IV BBC have the same engine mounts and the same bellhousing bolt pattern. A BBC longblock will fit in the 240-280Z without any “cuttingâ€, but be aware of complications in fitting the exhaust tract, in how far the oil pan hangs down (especially if you’re using the 9â€-deep truck oil pan) and how far the air cleaner sticks out (especially with a Performer RPM-type manifold). The blown 454 mentioned above has, I believe, changed hands, and now sports a SBC. There’s still a handful of BBC Z’s on this site. Mine has some sheet-metal mods, including a setback firewall location and some chassis reinforcement, but the rear end is stock (R200). Other BBC Z’s are back-halved. Bottom line – yes, it can be done, and no, the weight/balance issue isn’t necessarily a showstopper, but there definitely are complications. It is NOT as simple as the JTR SBC swap. And while the JTR-type SBC setback plates might work, it would be better to mount the motor to the frame rails (with suitable reinforcement).

I visited the Monrovia p-n-p (east of LA) the other week - my first visit to a self-serve junkyard in about two years. There was only one Z in the entire yard (a 280Z). You folks in California are lucky to have p-n-p junkyards. Here in Ohio they're extinct. That said, prices for used parts are definitely going up. This is strange, considering that prices for new or remanufactured parts at Autozone-type stores seem to be stagnating, or even declining. Would this be a consequence of Chinese manufacturing?

Considering that the differential failed while the halfshafts and stub axles did not, it's not inconceivable that your differential was damaged to begin with, and that one full-throttle clutch dump was enough to finish it off. A stock R200 in 3.54 or 3.7 ratio goes for about $75, and at that price, it's worth reinstalling a stocker, subjecting it to the same "abuse", and seeing if the failure repeats itself. The proponderance of stories about rear-end failures strongly suggest that a R200 should be OK for your application. That said, there's nothing wrong with a solid rear axle, especially if the car is a dedicated dragster. But that's major $$$ and requires considerable engineering.

If you’re comfortable with 350 hp I’d stick with the 236 heads; they should be adequate at this level. 400 hp should be possible with a little portwork. With no valve job (at all), my home-ported 236 heads reached something like 260 cfm at 0.500†at the local flow bench; this is about 25 cfm above stock. If one believes the rules of thumb, even the stock 235 cfm is enough to support 350 hp, easily. For the 236 heads I would recommend straight-milling them a bit to increase static compression – if you don’t plan to rebuild the short-block. If you do rebuild the short-block, get mild-dome hypereutectic pistons, such as what I bought (“Sealed Powerâ€). BTW most aftermarket BBC pistons already have their skirts coated. For the 236 heads, 0.007†of straight-milling gives approximately 1cc of combustion chamber volume reduction. For your application you only need to remove about 5 cc – but check piston to valve clearance. Chevy High Performance magazine has a web page with a database of most SBC and BBC head flow numbers. And if you search in this forum under “DCRâ€, several of Grumpy’s posts on dynamic compression ratio calculation should pop out. There are various sites where you can download a DCR calculation program – not to say that it’s difficult to write one yourself. What’s more difficult is reaching a consensus on what DCR value is OK for what octane value, and various other variables. It depends on combustion chamber shape, piston dome shape, quench, cylinder head material, alignment of the planets and color of the pavement. Well, not entirely, but sometimes it feels that way.

Something similar, though not quite as drastic, happened to my 280Z. It’s been sitting in my garage for about 5 years, sometimes with the windows open, sometimes closed. The mold is especially attracted to the vinyl of the door skins – but hardly at all to the headliner or seats. This is in Southwest Ohio, and the garage is basically in the middle of a forest, so the environment is quite humid.

I had a MK III Supra Turbo 5-speed (1987); bought it in 1995, sold in 2000; my first "sports car". Since I'm a low-rpm guy, this car was nothing but frustration. When I lived in Los Angeles, I once went to Pomona for test-and-tune. After one of the best launches of my life, I reached... 86 mph @15.8. True, by then the head gasket was not far from failure (again!) and the turbo only spooled to about 5 psi. Before the Supra, I had a Corona (1970's RWD precursor to the Camry) and 1983 Celica. The Supra turned me away from Toyota - until I ended up with a early 1990's Corolla (reached 225K miles before the rust killed it). Bottom line - with the proverbial right mods and right driver, Supras can exhibit impressive performance, but a stock Supra with a mediocre driver isn't particularly impressive.

If this is a 1979 then it’s a Mark IV 454 with flat-tappet hydraulic cam. The 236 heads have 225cc intake ports and 119-122cc combustion chambers (depending on which reference source you believe). If your intended application is for the truck, then the peanut-port heads are entirely adequate. Port-work to consider would be partial port-patching (don’t go all the way – see below!) to an Edelbrock Performer intake, clean-up of the inner-radius in the exhaust ports (exhaust ports on 236 heads have a very sharp inner-radius corner!) and bowl-blending on all the ports, as often one finds something like 0.100†“steps†in the port casting. And as the others already mentioned, the pushrod-through-the-rocker situation is probably a symptom of a wiped cam; which means a complete teardown. If this engine is intended for a Z (ambitious, but not impossible) then you’re looking at $2000 for aftermarket heads and >$1000 for a suitable valvetrain (good lifters alone are $500!). Yes, there are cheaper alternatives, but they negate the performance advantages of the BBC. I started with a 454 from a 1978 Suburban – basically, the exact same engine as what you have. I did the above-mentioned port work on my 236 heads. When the machine shop pressed in new valve seats, the heads cracked; evidently, I removed too much material when trying to port-match with my Edelbrock Performer RPM intake. The port work took several months, with 1-2 hours a day, several days a week. This is with a Sears 1/4"-collet electric die grinder (basically a giant Dremel) with a range of grindstones, including a $30 carbide cutter. Even at 25,000 rpm with the carbide cutter, cast iron takes a LOT of time to remove – and the shavings are nasty! With glasses and a mask I still ended up with dust in my eyes and nostrils. So all that port work was for naught. Eventually I mustered the gumption to buy aluminum heads. In a truck the cast-iron Pro Topline heads would be an interesting option, but in a Z I just couldn’t justify not using aluminum heads, whatever the cost. For some time I’ve been waiting for AFR to bring their oval-port heads to market. But 2 years is long enough to wait! Brodix recently came out with their “Race Rite†oval port (271cc) heads – and that’s what I currently have on order. For my build, I used the block, crank, rods and damper. In hindsight, I should have gotten aftermarket crank and rods – or at least the rods. Because the short-block was built with 236 heads originally in mind, I bought 10.5cc-dome pistons, which give around 9:1 SCR with the 236 heads. The original plan was to use a hydraulic roller cam. The current plan is to use a healthy mechanical roller with the Brodix heads. Brodix can mill the combustion chambers down to 110cc, which gives (if I recall correctly) something like 9.6:1 SCR with a 0.039†head gasket. If you follow Grumpy’s posts, you’ll notice that this is quite low for a big block, let alone one with a mechanical roller. But the duration is pretty small and I intend to install the cam with considerable advance, giving a DCR in the 7.8:1 range (or higher). Anyway, my point is: keep it simple if your application is a truck, but if you’re going for a BBC Z, you’re looking at another $4K-5K to build the engine “rightâ€. That should give just shy of 500 hp and around 550 ft-lb torque

Dave88ss - another Dayton member - welcome! I think that makes about 3 of us. One of the few advantages of living in the Midwest is that land is cheap, and there's plenty of space for building large garages. I live in the boonies, and though home ownership has been an almost unmitigated disaster, the 24' x 40' garage is convenient.

Now your sig says that you have a Toyota Corona - man, that really brings back the memories! My parents had a '74, then a '76, and finally a '78. The '74 was an automatic - we trashed it when the transmission died. The other two succombed to rust or ill use. What sort of engine will you swap into these? Please don't make it a turbo.

Understood about the piston-speed constraint. But what do you think of the following train of thought: going from a 4.375 to a 4.5 stroke (for example) is only about a 2.9% increase in piston speed and displacement. If the engine maintains the same peak volumetric efficiency, peak torque should rise by the same 2.9%. And if the rpm for peak V.E. goes down by 2.9%, peak hp stays constant. However, for the same compression ratio the 0.125†extra stroke buys a 2.5cc reduction in piston dome (if I recall correctly the specs of your heads) to get the same compression as with the smaller stroke– and conceivably, with the smaller dome the result is a slightly lighter piston with slightly better flame-front propagation, hence better combustion efficiency. So, because peak hp hasn’t budged, the benefits in a racing engine are questionable – but in a street engine, especially in a relatively heavy car like the Corvette, the trade of extra stroke at the expense of reduction in peak rpm might make sense. Do you have a broad choice of gears for that Dana 44 (or whatever differential the Corvette uses)? BTW I’ve heard elsewhere that copper head gaskets are tough to seal for an aluminum head/cast-iron block application (yes, I know that your application is an aluminum block). This seems counterintuitive, and contradicts some discussions on this site – including, if I recall correctly, your posts. What’s your opinion on copper head gaskets in the 0.040â€-thickness range?

I second jmortensen’s comment. Life has improved IMMEASURABLY after getting married (at the tender age of 30). I even have more time to work on my Z, since there’s some one to share the housework! What ties you down, saps your energy and wastes your time isn’t a spouse – it’s the children. Avoid them as long as possible – or, ideally, forever. “Playing the field†only works if you’re a player by nature. Are you suave, resourceful, blessed with an attractive appearance? When I was 21 all that I did was study and save money. Between the 6 hours of homework everyday and the cystic acne, dating wasn’t an option. Regarding your vehicular dilemma, sell BOTH the Grand-Am and the Z. Your Z is a 1979 ZX, and please don’t take this as an insult, but it’s not a classic, and is unlikely to appreciate in value. So sell both of those cars and get an econobox beater that’s reliable, cheap to insure and easy on gasoline. As for figuring out what you want to do in life – well, that can only be accomplished in hindsight, and even then it's not clear! I know people in their 70’s – that’s right, in their 70’s – who are wrapping-up 45-year-long careers in engineering, and they still don’t know what they want to do, and they still have regrets over having gone into aerospace engineering during the Eisenhower administration!