What year motor and head to get???

[CoastGuardZ]

I know everyones gonna say use the search but here it goes anyway...

A local yard has a few 280zx's and one 260z 2+2. None are rebuildable by any means. I can pick up a whole Engine with everything on it for $250. I think this is pretty decent. Some of the cars are turbo some aren't. What year or what else should I look for on picking which one I want him to yank for me?

Plans are to tear down and make a pretty mean street motor out of it. It will get Carbs and all when it's time to find her a home. I'm looking to make ~250hp. The goal is that it will end up in a 240 and still look like a 240 motor With tripple carbs.

Is the turbo block better?

This could still be a couple monts away, but would like any input from you guys.

Nate:cross-eye

[ZmeFly]

best bet to me for the most power and drivability is a 82+ turbo!! and a five speed heheheh

intercool it boost it to 12# and watch almost everyone eat your dust:love:

[peterc]

I agree with Zme, newer = better. Datsun didn't change engines until 1984 (300ZXz) so anthing up til 1983 is interchangeable.

The newer engines have stronger blocks (especially the turbo models), the heads flow better, pointless distributor, etc, etc.

Good luck

Peter

[Bleach]

But since you said you are going to use webers, then don't get the turbo block. Typically, the best block/head combo is a P90 turbo head from the 1981-82 280ZX turbo and the F54 block with flattop pistons from a 1981-83 non-turbo 280ZX.

(1983 turbo head has hydralic lifters, avoid that if possible P90a)

That gives you the 8.8:1 compression right from the start, the closed chamber head for good quench, and the better flowing square port exhaust. The P90 is also cast like the N42 with the mechanical fuel pump blocked off by a bolt-on plate. I suppose you will use an electric pump anyway, but the option is there.

Stick in a performance cam, shave the head 0.008 and advance the cam to the #2 spot on the upper sprocket. Use the non-turbo electronic distributor. With headers and your carbs you're looking at about 200hp. I'm not sure how you plan to get 250. Most people can't with a normally aspired engine. Besides that, a properly modified fuel injection system will beat out those tripples in torque and high end power. But that's not the look you're after.

Putting in a 4.11 or 4.375 rear will help increase your wheel horsepower.

[Mudge]

If your going to stay NA get the F54 block which has flattops.

If you want more power + driveability go turbo, if they are $250 also heck, I would have considered the same thing plus the turbo's T5 would be nice (better OD).

[Bleach]

Keep in mind that the turbo uses the F54 block also, but has different dished pistons inside. If you get the proper head for use with the dished pistons, the turbo block/pistons are fine for an N/A motor. But if you use the turbo head and block without turbocharging the engine, you'll end up with 7.5:1 compression.

The T-5 has a slightly lower overdrive than the 1981-83 5-speed, but although the 81-83 n/a 5-speed has the highest overdrive it also has a much higher 1st gear. It was matched with a 3.9 rear so the high 1st gear didn't hurt acceleration. If you get the T-5 be sure to get the driveshaft too as the Borg Warner has different rear splines and is not a Nissan transmission. So the T-5 has a great 5th gear and you'll rocket from a stop with the low 3.5:1 1st gear.

77-79 5-speed

1st: 3.321

2nd: 2.077

3rd: 1.308

4th: 1:1

5th: 0.864

82-83 Turbo (T5)

1st: 3.5

2nd: 2.144

3rd: 1.375

4th: 1:1

5th: 0.78

81-83 n/a

1st: 3.062

2nd: 1.858

3rd: 1.308

4th: 1:1

5th: 0.745

The 81-83 5-speed is the "closest ratios" considering all have a 1:1 4th gear. that is a good match to a car using a 3.9 or lower rear differential. If you are still using a 3.5 or 3.3 then do not choose that transmisison. 1st gear will be a bit too high.

Oh, and 1980 has the same gear ratios as 77-79 except for 5th gear which is just slightly lower number than 0.864 but not quite 0.745

I "think" that is the one year the 280zx had a 3.7:1 R180 rear end??? It was the chageover from 3.54 in 1979 down to 3.9 in 1982.

[mike240]

is a 3.9 a good ratio to use with the turbo engine or would that be too low? if so, what is the best ratio diff to use?

[Victor Laury]

I have an N-42 block. I was going to rebuild this engine. Can it be refitted with flat top pistons? 10:1 sounds good to me.

[Mudge]

With a turbo your probably going to want a 3.54 or something similar, so you are in the gear long enough to build boost. I have an early 5 speed, and it feels like you shift into 4th twice with the .864, bleh.

[Bleach]

Very true, my little Datsun truck has a simular 5th gear and its hardly higher than 4th, but its there...

You can either swap pistons or just swap the whole block. The F54 casting is said to be a better design. I guess they had more ridges for a more rigid block.

The 280zx turbo comes with a 3.54

I know people who have put a 3.9 in their turbo and they liked it. 4.11 might be too low. You can also go somewhere in between with a 3.7 or even grab the 87-89 300ZX turbo rear for a 3.7:1 LSD!

[Ben]

I ran a 3.54 with my L28ET, it was great, but I liked the extra power & acceleration that the 3.90 gave me. My 240Z will initally be using the stock 3.90, but I have a 4.375 R200 LSD to go in. Top speed will be ~100mph, but I expect to get there VERY fast :classic:

[texasz]

I'm new to the technical aspect of cars also as well as Z cars. What it NA or N/A? I see it throughout the posts and have not figured it out.