78 280z engine swap

[ldrofdpac]

Hi,

I bought my grandson a 78 280z. The body was very good. the motor had lots of blow by. I found a brand new motor that had sat for a while. when I got my motor out I found the exhaust ports on my engine were round and the new one was square. My old engine was as L28 my head was a N47. My new one had a P90 head. I was told that this was a turbo engine, with a lower compression ratio. Can I mill the head and get the compression retio back up.

[NewZed]

Somebody would probably trade you a good NA motor straight across, with some cash, for that turbo motor.

 

You'd probably spend more money on the machine work and parts than you would just buying another engine. The turbo engine should have a turbo cam also, which wouldn't be optimum for NA.

 

Just an opinion.

 

Edit - you could also swap the P90 head for an N47 head and get the 1978 engine's compression ratio, since the turbo engine will have dished pistons like the 1978 engine. Plus you'll be able to use your round port exhaust manifold, which is not recommended for square port exhaust. Just thinking...

Edited June 16, 2012 by NewZed

[BluDestiny]

You can shave the head, but read this first:

 

http://datsunzgarage.com/p79/

 

This is a p79 head but is nearly identical to a p90, so the mod is the same.

 

As Newzed said you'd be spending quite a bit on machine work, so it may just be easier to sell your longblock and buy a used running NA motor.

You can also swap the head, and while its out get machine work done to it since it probably needs it.

 

Personally I don't trust "rebuilt" long blocks. When I was 17 I bought a "fresh" longblock off craigslist and after 2 months it blew. The PO had hidden a crack in the block using JB weld and painting over it. My coolant leaked out and the engine shot a rod out of the block on the freeway.