Pay attention to head gasket bore size w/ aftermarket heads
10-02-2015, 09:45 AM
#1
Pay attention to head gasket bore size w/ aftermarket heads We're getting into some Winter mods early & happened to notice that our stock Cometics are protruding into the CC of our AFR 205's. It's slight & can't be clearly seen. Found it when we were gonna scribe for valve shrouding & then measured w/ micrometer.
Went to the AFR site & found that their gaskets are .020" larger in diameter than Cometics (stock bore head gaskets). So, it must be that the AFR CC design already incorporates some mild valve shrouding & to the point where larger head gaskets are needed. May have also been that these were slightly out of tolerance. These heads had not been touched other than decking, then polishing runners & bowls. Regardless of whether or not this was the norm, pay attention to the largest distance from edge to edge of aftermarket head combustion chambers.
Went to the AFR site & found that their gaskets are .020" larger in diameter than Cometics (stock bore head gaskets). So, it must be that the AFR CC design already incorporates some mild valve shrouding & to the point where larger head gaskets are needed. May have also been that these were slightly out of tolerance. These heads had not been touched other than decking, then polishing runners & bowls. Regardless of whether or not this was the norm, pay attention to the largest distance from edge to edge of aftermarket head combustion chambers.
10-02-2015, 05:35 PM
#3
I may have known this @ one point & time. Have had 'em for so long & have had 'em on & off so many times that we probably simply forgot & replaced the gaskets w/ stock bore gaskets @ one point in time. Because during normal installation we only see how the gaskets fit onto the block, not the head, the CC intrusion wasn't noticed 'till we laid out the head gasket in order to mark the intake valve shroud area on the head.
10-02-2015, 08:42 PM
#4
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Where's "know it all" to tell us how it really doesn't matter? 
