pulled the heads off a pontiac 350 and a 400 and the 350 is more the likly stock and the 400 had alot of unknow perfromance stuff done to it I noticed both seem to be flat top pistons but the 400 has a buch of valley of some sort?????
hitacethe indentations in top of piston provide valve head clearance67gto
The 400 is a stock piston they are just valve recesses.
+1 the 400 has flat tops with 8 valve reliefs.
Engine builder,self taught auto body guy.Horsepower sells engines and torque wins races