Stopping the knock: Lower compression and ported heads...

i run 11.25 with 205psi cp on pump 93 360 with j heads, quench cools the combustion chamber i would run a gasket that is around .025 to no more than .030. round off all sharp edges on the piston and head chamber, have to run a plug that is at least two or 3 steps colder, obvious stuff like heat crossover blocked, fuel cool, jetting correct, no oil in combustion chamber, should only need around 34 total with good quench.black specks mean detonation usually, also if plug ceramic is yellow that means cyl temp is rising very quickly.