Guest sweething_2_5 Posted July 4, 2003 Share Posted July 4, 2003 Ok i am wondering what would be better for performance and why..... in choseing a head for my 77 280z.... i have both a n47 and an n42 either would need to be rebuilt but... which would be better...... also i have a header for the round exhaust n 47 and dont really want to buy a square exhaust header but will if thats what will give me the most hp..... Thanks Jason[/size[/b] also would it be better to regrind the cam i have or... buy the cam kit from msa with all the internals to rebuild the head????? Quote Link to comment Share on other sites More sharing options...
Guest 240hybrid Posted July 4, 2003 Share Posted July 4, 2003 I think that the N42 is better performance wise. This is what I have on my NA 2.8 spare motor. It develops a higher compression than the other head you listed, but I believe the N47 would be your next choice. As for cams I talked to Jim Thompson with Sunbelt about the schneider kit that I got from MSA as part of their cam kit and he told me if I was wanting to modify the lower end and make the motor a 3.1 (which I was thinking of doing at the time) the schneider would tear things apart. I ended up sending it back and deciding to go turbo. Im not saying that MSAs kit is junk, but from what Jim said their not good for heavily modified motors and a custom grind should be made for the setup to match the major modification and get the most power you can from it. If you dont plan on doing any heavy mods beside header, exhaust, throttle body, air intake, then I would say go with a MSA cam kit to boost up your power. Especially when you go the motor breathing very well with all the other modifications, its time to throw in the cam. Just my .02. Chase Quote Link to comment Share on other sites More sharing options...
Guest zline Posted July 6, 2003 Share Posted July 6, 2003 N42 is better hands down. The N47 will give 1. lower compression 2. lower power output. why? well its simple, the N42 doesnt have the steel exhaust liners that act like a redhot match to burn uncombusted fuel for smog nazis, it'll also yeild less compression which on a n/a motor will kill peak hp. If you're going turbo - pick up a non hydraulic p90 for best results. Quote Link to comment Share on other sites More sharing options...
Guest zline Posted July 6, 2003 Share Posted July 6, 2003 N42 is better hands down. The N47 will give 1. lower compression 2. lower power output. why? well its simple, the N42 doesnt have the steel exhaust liners that act like a redhot match to burn uncombusted fuel for smog nazis, it'll also yeild less compression which on a n/a motor will kill peak hp. If you're going turbo - pick up a non hydraulic p90 for best results. Quote Link to comment Share on other sites More sharing options...
Guest sweething_2_5 Posted July 8, 2003 Share Posted July 8, 2003 Well is there ne way to get rid off those exhuast liners??? Thanks Jason Quote Link to comment Share on other sites More sharing options...
Guest zline Posted July 8, 2003 Share Posted July 8, 2003 the $ you spend to do it properly etc., etc., you can have a nice head (E31/88) w/o them, and even get some work done to them Quote Link to comment Share on other sites More sharing options...
Guest mescalinedreamz Posted July 8, 2003 Share Posted July 8, 2003 i think some people just go by rumors, but a couple of websites say that the flow isnt that bad, i think you should go with the one with less miles and the one that looks better,,and you can always sell that header and extrude hone the old exhaust manifold like that guy did in the magazine,,since after all the stock exhaust manifold will outlast the header and will cut down on evil heat in the engine area,,so go out to that junker and pop that head off and when you pop the other one off compare them and see whats in better shape! Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 10, 2003 Share Posted July 10, 2003 i think some people just go by rumors, but a couple of websites say that the flow isnt that bad, i think you should go with the one with less miles and the one that looks better,,and you can always sell that header and extrude hone the old exhaust manifold like that guy did in the magazine,,since after all the stock exhaust manifold will outlast the header and will cut down on evil heat in the engine area,,so go out to that junker and pop that head off and when you pop the other one off compare them and see whats in better shape! Probably good advice. Also, according to the data that I have seen, the combustion chamber volume for the N42 and N47 are the same, meaning that they should give identical CRs. The main difference is the exhaust ports. Quote Link to comment Share on other sites More sharing options...
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