Chaset80

I知 building a 408 with a lq4 block and 821 heads. What head gasket bore would be the best to go with? I知 guessing bigger than 4.065 because of the size of the LS3 chambers? Should 4.08 work? I知 a noob when it comes to head gaskets for custom builds. 4.030 bore, but my heads are off of an engine with a 4.065 bore. Any help or recommendations appreciated, folks! Engine will be naturally aspirated and sprayed a moderate shot.

KCS

iTrader: (20)

The OEM 6.0L gaskets are 4.050" and are used with LS3/L92 heads all the time. I would prefer a little larger, like the OEM 6.0/6.2L gaskets which are 4.100".

MuhThugga

I would use the 6.2 gaskets. You want to match the gasket bore to either the chamber or the engine bore, whichever is larger.

tech@WS6store

iTrader: (2)

Youll need the 12610046 ls3 head gasket.
The gm 6.0s with rect port heads use the ls3 head gaskets also. Like the l76 in the G8 GTs. Same with ly6 etc.