Pyro

I have been running a similar set up for 6 or 7 years now. Completely Stock 76 efi with a bell fmu and locked out stock ignition. But I use to 10-14 psi of boost (adjustable) and 28 degrees of timing with 7.4:1 cr and a NA cam. This requires a good efi pump (like a bosch 044) and 80 to 110 psi of fuel pressure (8:1 fuel pressure/turbo boost). With the stock NA setup (8.3;1 cr) you can run around 24 degrees of timing with 7 to 8 psi of boost and 65 psi of fuel pressure. Use the vacuum advance as normal. FYI, stock turbo ignition timing is 24 degrees at idle. In your case, I would use a P90 or P79 head to lower compression to 7.4:1 cr and use 8 psi of boost with 30 degrees of timing (locked out), and 65 psi of fuel pressure. You need to pull out the distributor and disassemble until you get down the the mechanical advance slots. Once you get there, lock out the advance (rtv in slots, wire instead of springs, welding, lots of ways to lock it out). Megasquirt is a much better way to manage a turbo setup but the fmu and locked ignition works OK with stock boost.

The stock pump is not mechanical on a 75 280z. The stock 75 pump should be fine if it is in good condition. If not, the msd 2200 efi pump is a good one.

The nice thing about a th350 is that it has no TV cable like 200r or 700r. And the th350 seems to always shift at the right time, unlike 200r and 700r's. And cheap rebuilds for the th350. But no OD with the th350 is an issue if you build a mild engine (low rpm engine) and plan to drive a lot on the highway. A friend on mine used a th350 and love it but didn't like the rpms on the highway even through we put in a 2.87:1 1980 vette diff in the rear. However, if you put in a cam like a 292H compcam , 3000 rpm stall, and use a 3.55 gear, then you will not miss the OD that much.

Get a 280z as it will already have fuel injection and a compression ratio you can add a low boost turbo system. If you are good a rounding up good used parts then you can turbo charge a 280 for 300 to 600 dollars and do it over the weekend if you use a FMU for fuel enrichment and lock out the ignition timing curve. From my experience you should be able to run a 14.5 @ 95 mph in the 1/4 mile without an intercooler with stock 280zx boost (7-8 psi) and around 14.0 at 100mph with an Intercooler.

I would say the smaller journals have less drag (less frictional internal losses). But more stress due to the same load over a smaller bearing area. stress=load/area.

1.6's are the "easy fix" for a cam with low lift. They especially make a difference on a stock cams. Otherwise, if the cam already is ground with a lot of lift, then adding 1.6's can lead to problems. More lift is not always a good thing as it can wear out springs and cam lobes much faster.

World class or non-world class T5 are both good. The important thing is to get a T5 from a V8 car and not a V6. The number of splines on the input shaft is the way to tell if it is a V8 or V6 trans. I forget the exact count but i think it is 26 splines on the V8 trans and around 10 on the V6 trans (easy to see). Just go easy on the trans. Shift kind of slow, try to avoid full power in 5th gear and dumping the clutch.

Forget the big block or even a small block. Much cheaper to buy a late model 5.3 with trans from fan to tailhousing. And you can make impressive power numbers with a late mode LS style engine while still maintaining good street manors and good mpg. Spaces and line returns will make your post easier to read.

With the right cam, valve springs, intake, and a short block in good shape, then no problem to rev a stock 327 or 350 to 7000 rpm for quick burst. (drag race). Not for extended time periods at 7000 rpm.

Redo the compression calculations with the piston sticking up 0.010" out of the block. Because.... That is what the stock setup does. (sticks out of the block). If you use a mild cam with stock valve springs you don't need to resurface anything. Get the stock cam reground, add some thicker lashpads, and go. Increase duration but keep the lift low and the lobe ramp slow (like a stock cam). The later the intake valve closes (bigger cam) the eaiser it will be to run high compression with pump gas. That is why I mentioned it.

I would add a little more cam. Get the stock cam reground to around 260 degrees duration with 0.420" lift (212 degrees at 0.050) at delta cams ($100) and get some 0.160" lashpad from courtesy to make up for the regrind. Should work with the stock springs and efi and would be a ton easier to tune with 10:1 cr as compared to the stock cam.

The tank will be in the way if you want to run exhaust on the passenger side. A single 3-1/2 exhaust system will be easier to run. But no need to change the tank just because you are using a V8. I would use the stock 280 efi pump even if you are using a carb. Just regulate down the pressure with a return style Aeromotive fuel pressure regulator down to carb pressure.

I would double check that. If you wipe out a cam lobe then the lobe/lifter metal will eat up the engine bearings. I measured a set of vortec heads a few years ago and the retainers hit the valve stem seal at 0.420". http://www.ryanscarpage.50megs.com/combos1.html Check out combo 73. Close to your build with a little bigger cam. Can down load the site summary as an excel spread sheet.

There are also big differences in the blocks. Namely, low tension rings in the LS to reduce internal engine friction. And a roller cam.

The vortec heads will add compression and flow over the 882's. and the vortec head woud require less ignition timing. I would say a 30hp or 40hp increase with your cam (268H). Should make a 350hp 350 with vortecs. The vortec heads will need to be modified to run a cam that big.

Heads are most likely 882's. Should run ok. I would say 300hp or maybe a little more if the exhaust system is good.

And a 3.54 wouldn't be enough gear for a 7500 rpm 327. Would need a 4.56 gear and a 4500 stall converter to use an engine like that. Not a street setup at all. This is why NO2 is a good idea, as it also increases torque (even more so than hp). So can use less gear and stall.

Want some real numbers, ok. My 71 240 with a 450hp (crank hp) 362 cid (200cc dart heads (64cc), 292H comp cam, full length headers, rpm intake, 750 holley, 11:1cr, zero decked block, flat tops) with a T5 5 spd. Ran 11.7 at 120 on the motor and 10.7 at 135 on a 200 shot on N02. And 1.5 second 60 footers with MT drag slicks. After 120 mph, I had to change axle and u-joints much more often. An automatic trans might be a little nicer on the drive line. Over 130, maybe 5 to 10 runs before something broke. And the 240z is lighter than the 280z. Never measured it but I would guess around 2800lbs with me in it. ET is hard to repeat with questionable traction. However, trap speed will stay fairly consistent. First run I did with my V8 conversion was 12.7 at 110, second run was 14.0 at 110. Took a few years to tweak it into the 10's but then it wasn't fun anymore with all the rear end breakage. As for suspension drag racing setup, start with the heavy springs in the rear and stock springs up front. And lose the front swap bar. This setup also cures front end plow (under steer)

Why not do the turbo conversion? The power from the turbo is worth the work. You could just turbo charge the 75 engine. The money you spend on carb, you could junk the stock efi and do a mega squirt system. Flat tops with a P79 is 8.8:1 cr. The stock piston sticks out of the block around 0.010". Most people forget to include this in the cr calculations.

A 11second flat 1/4 mile will take 120 to 130 mph trap speed (depending on traction). A Z with street tires and stock rear end will have bad traction So, plan on going 130hp in the 1/4 mile. That will take 620hp at the crank with a 3000 pound car. I would build a 400hp 327 and add a 200hp shot of n02. Will be tough to make 620hp with a 327 with no power adders. If the traction is good then all you need is 485hp to make 120mph in a 3000 pound car.(total weight). This can be made with a 327 but more gear would be required (3.90 or 4.11). I found the stock 1/2 shafts and axles start to break at mid 11's, 120 mph range.

You need a bigger cam to run 11:1 cr with pump gas. I run a 292H compcam with 11:1cr with no issues. 292/292 advertised, 244/244 at 0.050". A 383 with vortec heads and a "big"cam can still have good low rpm power due to the small ports in the vortec heads. But I would still recommend a 3000 stall with a cam in the 290 degree range.

That is worth 2600 dollars. Lots of expensive parts there. And power output could be as advertised if the duration is long enough. However, not a good street engine. Not at all. I would look for a used 96 to 2000 350 vortec engine (complete). These engines came with factory roller cams and vortec heads. Should be able to find one in good shape for $700. Add a cam, minor engine refresh, a little head work, and make a streetable 400hp. Check out this 350 build http://www.superchevy.com/technical/engines_drivetrain/completebuilds_testing/sucp_0910_chevy_350_engine_build/viewall.html Or go LS. Can get a 5.3 liter cheap. But will be a little harder to install and get running (ignition, intake/carb, or efi)

The car is currently at my house but really don't want to jack it up and take a picture. However, we will be pulling the engine out fairly soon to drop in a TPI engine and then I can get a photo. But the narrative should be enough. The Y pipe is at the start of the rear A frame to make room for all the other stuff (flex jonts, H-pipe,and dual bullets).

I did an exhaust system for a friend with a 350 in his 77 Z. I first went the easy route and built a system with 2-1/2 duals off block hugger headers to a y pipe (dual 2.5 to 3 inch) then to a 3" turbo muffler. The drone was terrible. The worst I ever heard!!! I'm still having nightmares about that drone. crazy droning!!!! Even the exhaust sound outside the car sounded bad. The car was undrivable. So, I put in a H pipe right after the trans then two 12 inch dynomax bullets before the Y-pipe. Now the engine sounds really quiet in the cabin and the exhaust note outside the car sounds really nice. Later, I put in some flex joints right after the headers to reduce vibration from the exhaust system. Got all my stuff from summit racing (mandral bent pipe, mufflers, flex joints)

Flat tops would be the best for a 350. However flat tops with 64cc chambers (vortec heads) could make the compression too high for a 268 degree cam (depending on deck height of the piston). Do you know the piston deck height that you have now? (how far the piston is below the deck at tdc). I would shoot for 9.5:1 cr with that cam and those heads. But 8.75 isn't bad. 9.5:1 would be worth about 3% in extra power over 8.75:1. That will be 9hp on a 300hp engine. The good news is 8.75:1 should allow the use of 87 octane fuel which is a plus. Furthermore, you could more safely add a little shot of NO2 with the lower compression. If it was my build, I would use....... Hyper 4 relief flat top pistons (cheap), Vortec heads with proper springs and the typical machine work on vortec heads required for extra lift, 280H compcam, not a fan of xtreme cams due to noise and prone to go flat. RPM intake with a square bore, not airgap rpm due to slow carb warmup on the street 3310 holley 750 cfm Long tube headers would be best but block huggers will work, Dual 2-1/4" from the headers, H-pipe, then dual 12" dynomax bullets, then a Y-pipe, to a single 3 or 3.5 pipe, then a turbo muffler on end. 3000 rpm stall if you have an automatic, 10 inch converter 3.90 gear would be best for acceleration, but almost any stock Z gear would work due the the light weight of the z. 20 degrees initial timing, 36 degree total. Then get an adjustable vacuum advance and add another 10. Finally, use ZDDP oil additive to make the cam live a long life. www.zddplus.com