[aronhk_md]

Can anyone shed light on how boost and compression play a part in the life of cylinder head to block seal? In other words, at what point does one need to o-ring block, heads, or both? In one of the threads recently posted Bruce mentions a 406 chevy that was boosted all the way up to 28 psi, with pump fuel at lower boost, then race fuel later, and it made me wonder at what point our pontiacs need these mods. I realize that cam design plays a part here too, but would just like to hear some thoughts on the matter.

Also, take a boosted application designed mostly for the street and an occasional foray to the track.

Is it safer for a stock 455 block to make X hp and torque at 10 psi boost(just a relative # here), but allowing the engine to spin higher to say 6500 rpm (again, just a relative #), versus the same block tuned for a lower rpm range (say 5800 rpm max) and 15 psi in an attempt to maximize mid range. Assume the rotating assembly was well prepared but mostly stock.

Hope to get everyone's input on one or both questions.