When I do my little rebuild/refresh on my 72 240z motor, L24 stock, I would like to put a better head on it, its got an E88 right now. I was wondering if an N42 would be my best choice? How much can they be bought for? How much for new seats since they'll probally need them. Will this give me better compression on my engine? Any ideas on power gains over my high milage stock E88? Thanks

If you choose the N42 head you will get bigger valves but you will loose compression on your L24. The N42 head, on a stock L28, only has about 8.3 to 1 compression. Of course the L28/N42 has dished pistons and your L24 has flat top pistons. Check out the numerous posts on heads for better details.