I'm getting ready to put the top end of my motor together. It's a Gen III 4.8 with flat top forged GM pistons with valve reliefs. Stock rods with ARP rod bolts. The cam is a custom grind blower/nitrous Comp Cam 218/239 115 .612/.623, hand ported 853 heads with PAC spring kit. Melling oil pump.

I was told to use LS9 head gaskets, but i think the bore on the head gaskets will be too large, (like 4.100" compared to stock 3.780"). What head gaskets should i be using for the smaller bore?

 

just go oem bore. felpro makes some nice silicone coated MLS gaskets.
thats what im using on my build. so far, so good.