datzenmike Posted April 25, 2007 Report Share Posted April 25, 2007 Can you confirm this:? '81-'83 L28 had three different heads P47, P90 and P90a, the last two were turbo heads? All the above heads were 54cc ? even the turbo heads? All '81-'83 engines had flat top pistons only? So compression was 8.8? on all motors. I was under the impression all of the above was true but need to know if not, and what are the correct ones. thanks, mike Quote Link to comment
Bleach Posted April 30, 2007 Report Share Posted April 30, 2007 Not ture. N47 was the pre-1981 head. Open chambers. not sure on CC but has fewer CC than the later closed chamber heads. 1981-83 non-turbo heads are closed chamber P79 1981-82 turbo is the P90. Same as the P79 except for the exhaust ports are rectangle instead of round. 1983 turbo is the P90a. Same as the P90 but with hydralic lifters instead of the manually adjusted rockers in all previous heads 1981-83 non-turbo did have flat top pistons with 8.8:1 compression 1981-83 turbo has dished pistons with 7.4:1 compression. Same volume heads as the NA Quote Link to comment
datzenmike Posted April 30, 2007 Author Report Share Posted April 30, 2007 Thanks Bleach it was worth the wait, lol. Quote Link to comment
hughdogz Posted January 27, 2009 Report Share Posted January 27, 2009 (edited) 1981-82 turbo is the P90. Same as the P79 except for the exhaust ports are rectangle instead of round. Sorry to dig out this rusty thread...had to see what the first z-car post was after trying "archive view" :rolleyes: Anyway, I have an 8/82 Turbo with a P90A head with mechanical lifters. They're out there... Edited January 27, 2009 by hughdogz Quote Link to comment
Bleach Posted January 27, 2009 Report Share Posted January 27, 2009 Anyway, I have an 8/82 Turbo with a P90A head with mechanical lifters. They're out there... Is it for sure the original head? BigPhil has a video of how to install mechanical lifters in a P90a. :cool: I should check mine though. I never did take the valve cover off on my 1983 Z. Quote Link to comment
lynchfourtwenty Posted January 27, 2009 Report Share Posted January 27, 2009 lol, BigPhil here.. an i jus wanted to say.. LMAO!!! dude that guys fuckin halarious.. :lol: Quote Link to comment
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