s2000sccaracer

Will 87.5mm pistons (looking at CP) clear an AP1 head, without needing to modify the head or using a thicker head gasket? Using a thicker head gasket will defeat the purpose of going with a larger dome volume to bump up the CR. Rules allow 12:1 max CR.

MorngWoodStewie

Best bet would be to check the piston top to deck clearance and then factor hg crush clearance, I would assume you will be fine tho right off the bat. On my H, I went a point and 1 half higher cr. And an entire mill larger. 87 to 88. 10.0:1 to 11.5:1. With a stock head.
If the outer diameter of the piston is even flush with the bore, I think the hg crush alone is enough.

I would be more concerned or focused on making sure the p2v are good or checking other possible setting on gears to see if u can tune the cams.

s2000sccaracer

Thanks. I'll be sure to measure the clearances.

MorngWoodStewie

As long as u have clearance, u still should only go max 1 mill larger then head, and I think the reason is more about the quench and there being a edge in the combustion chamber possibly creating pre ignition.
I matched hg to bore as well.