Guest Anonymous Posted January 16, 2003 Share Posted January 16, 2003 My friend and I are in the process of fixing up two different Z's, Mine a 73 240, which is slated for a 302(already being built). And his, a 76 280z. Well we got drunk one night and put the carbs, and header from my 240z on his car and completely removed the fuel injection and computer etc.. Problem, we still have the EFI head on it, injector ports, and round exhaust, Looks like lots of restriction to me, what would be a good square exh, non injection head to start with. We want to port it get a good valve job, the works. I just need to know where to look and how to identify a good head. Any help would be useful. Thanks. Quote Link to comment Share on other sites More sharing options...
Mike C Posted January 16, 2003 Share Posted January 16, 2003 Want (relative) big power cheap? Get an N42 head (75-76 280 with square ports and small chamber) and a junkyard F54 shortblock with flat top pistons. N42 and the current N47 head on your buddies 2.8 are same chamber size. On a mild motor, the exhaust liner round port head isn't much different powerwise than a different head. Compression makes a big difference in an L motor, thus the flat top shortblock. Only other way to get more power then is a cam swap, and all of a sudden, its not a "budget" project anymore. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 21, 2003 Share Posted January 21, 2003 Thanks for the answers, and amazingly enough, I was looking through my garage and found an N42, it has round exhaust ports however, do all n42's have round or are some square? Also, is shaving the head surface an intelligent way to boost compression of these motors? how far can you go without P-to-V clearance problems? and is it worth the money (I am going to have the head ported and worked over too). Thanks again Quote Link to comment Share on other sites More sharing options...
Mudge Posted January 22, 2003 Share Posted January 22, 2003 I have 3 N42s, I'll be selling one, one is on the 240 now, and the other will be worked on further (its already ported a bit). The main weakness of them is bronze seats, other than that they are a good head from what I know so far. N42 is a square port head, round ports supposedly are not as bad as they are sometimes made out to be since mainly the liner was misunderstood as a restriction device. Huge amounts of exaust flow is not wanted anyway, efficiency yes, but 65-75% IE ratio is often desired, not more than that. Quote Link to comment Share on other sites More sharing options...
BRAD D Posted January 22, 2003 Share Posted January 22, 2003 Mudge, did you get the heads that I sent you? what do you think? i hope you like them. Quote Link to comment Share on other sites More sharing options...
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