Looking into finding a P8R head to eventually put on my built block and only really had one question.

The P8R head has an 84mm combustion chamber? My built motor right now is a Benson sleeved block bored to 84mm so it would be a nice match. So replacing the P75 with it would drop the compression slightly. The block has 9.7 CP pistons in it so it wouldnt be that big of deal. If anyone knows how to do that calculation please point me in the right direction

Only real question is will the valves clear the pistons?

Edit: According to CP's catalog, "4 - Works w/ B16A / B18A / B18B / B18C Head". But those heads do not have 84mm chambers

 

http://www.zealautowerks.com/bseries.html


its a 47cc combustion chamber size on the P8R when you put that in, make sure you use the proper piston specs

also, the CP pistons should already have 33mm valve reliefs

 

Well I couldnt find the dome height so I back calculated it using the B16A specs CP uses to get 9.7:1. I got -8.48 which puts me at 9.36:1 right now and will drop me to 9.08:1 with the P8R

 

You should be ok, the only issue running p8r heads is when putting the 84mm head onto a 81mm ls block. but since your bored you should be fine, and the cp's should have the correct sized valve reliefes. but jst to be sure when installed check valve clearence. the slight drop in compression if any wont make much difference but it will need a retune with the larger valves

 

Wow you are really stepping up with your coupe man! Any plans on changing your manifold for more power as well? You should be fine with the P8R since your sleeves are 84mm also. And I thought that most off the shelf aftermarket pistons come with valve reliefs for VTEC sized valves anyway?

 

They are. I will clay the motor when the time comes to check anyway.

A ramhorn should pick up a decent amount of power. But the car is already a monster in its own right. Im just going to try and drive the hell out of it this summer and not spend more money trying to make more power I cant put to the ground lol

I just need something to work towards otherwise it gets boring ya know