It better not fall out of tune at all.
I have a 463 with Dave`s fast burn chambers. 72cc round port Eddys. 20cc Ross dish piston. It`s at 10.3 static with a 246/253 on 112 cam degreed at 107.5. Last I checked, it`s at 175-180 cranking pressure. I don`t have detonation BUT, it will run on sometimes in the summer down here. This is with 93 octane.
That will give you a clue.
