Greetings everyone. I've tried posting this question on another Z car forum but got very little specific feedback (I'm sure its been covered multiple times but I can't find archived posts with specifics).
My son just bought his first car, a '77 280X that we are rebuilding. We just gutted it down to the bare body last weekend which was fun and a great experience for him. My question is in regards to the engine performance mods. We currently have a N42 and a N47 head since that is what came with this project. (the N42 appears to have been rebuilt), the bottom end is still stock with the dished pistons which I understand yields a 8.3:1 compression ratio with these heads.
I'd like to bump up the compression to around 9.8 and use the new cam that came along with the car. It is a reground External oiled cam on a Nissan core by Delta camshafts with .460" of lift and 260 degrees 212@ .050" so perhaps I should be looking to stay around the 9:1 compression target.
I need to CC whichever head is best to use to verify actual compression ratio and figure out which head gasket to use. Its been suggested that an umilled N42 and flat tops with a Nissan head gasket puts this in the 9.8:1 ratio. I've read multiple ways to increase compression on the various Z forums but haven't found a real concrete answer. Do I install new ITM flat top pistons (with or without the two valve relief cuts) and just use one of the above heads OR do I need to find a P79 or P90 head to use flat tops. I did find datsungarage.com in which he mills a N42 head .080" and uses the dished pistons, is that a better way to go??
I'm sure this has been done multiple times before but I'm having a hard time finding all the info in any one spot. Which way provides the best bang for the buck?
TIA
