Help me decide engine/head combination - Turbo Application

[datsundoug]

I have a 280z that I am restoring.  I have several engines that I have collected over the years and want to come up with a gameplan on which combo to use.  I know a lot of it is preference, but I was hoping to hear your thoughts and why you think it would be the best combo.  I'm planning on installing forged dished pistons (CP brand) in any engine I decide as well as a full rebuild.  I'm not exactly sure at the moment what compression/dish the pistons are.  They say 8.0:1 compression on the box, but I'm not sure what engine combo that was from.  They are new, but i bought them second hand.  I will be installing a HY35 turbo and Megasquirt.  No initial thoughts on horsepower yet.  I currently have the following:

 

77 280z engine - N42 block/N47 Head (ran good - burned a lot of oil)

78 280z engine - N47 block/N47 Head (heard it run, never drove it)

79 280zx engine - N42 block/N47 Head (never heard it run)

8? 280zx turbo engine - F54 Block seized/P90(not sure if its an A yet)

83 280zx turbo engine - F54/P90A Head - Heard it fire up on starting fluid - Good oil pressure

 

What combination do you think is best?  Am i gaining anything other than the siamesed cylinders with the f54 block (I could possibly sell the block as is if I don't use it)?  Are all the rods identical?  Is the P90a head actually the best for turbos, or has that been disproven?  My initial thoughts would be to use the 83 f54 engine and p90a head but I would like to keep my compression close to 8:1 as i can.  Any opinions or suggestsions are welcome.  Thanks.

 

(I think i got the 77/78 280z engines with the correct codes, but they started blurring in my head of which is which so they may not be the exact combo that I listed)

[NewZed]

I'm planning on installing forged dished pistons (CP brand) in any engine I decide as well as a full rebuild.  I'm not exactly sure at the moment what compression/dish the pistons are. 

This is just a bad focal point for an engine build.  You'll be spending a lot more money on other parts, maybe more in the long run trying to build around a set of pistons.  It's more of a piston build then an engine build.

 

Unless they have sentimental value, you might be better off to design an engine then see if the pistons fit it.

[NewZed]

I have a 280z that I am restoring. 

 

8? 280zx turbo engine - F54 Block seized/P90(not sure if its an A yet)

83 280zx turbo engine - F54/P90A Head - Heard it fire up on starting fluid - Good oil pressure

 

It's not a "restore" if you're putting a turbo engine in it.

 

Isn't the last engine the obvious choice?  Designed for a turbo.

 

The other part of using those pistons is if they're over-size or standard.  If the block you choose needs to be bored you'll need pistons of the right size.  Something to consider.

 

With Megasquirt you can use a turbo on any of those engines, and tune to make it work.  So, picking the highest quality engine might be the most effective way to go.

[Tony D]

Bad premise... F54/P90 STOCK BUILD.
Trash the turbo and get a proper one.
Have the head  ported and cammed properly.
Tune to 400HP and 7000 rpms.

Pull Gasket and head, inspect for detonation signs. Have CP pistons  cut to match combustion chamber in head...and at 7.9-8.0 to one. If they are  just dished flat tops without a combustion chamber shape sell them to somebody else, you don't want them. Buy another set with a proper mirrored image dish in the crown.

From there, tune from 7000 to redline and terminal horsepower which should easily be around 500 hp at 7.800 if using a GT35X with 8 psi of boost.

Nice ride.

[Svt40]

Its a common misconception that the F54 blocks are Siamesed. In fact its the n42 blocks that have the front three and rear three cylinders all attached. F54 blocks have coolant passages between all cylinders. However there is no "better" block, they both work without difference. The blocks on these engines certainly are not a weak point in a build.