Poking around the Rock Auto website, I noticed the L36 calls for the FEL PRO 9917PT (left) / 9918PT (right) head gaskets. The L67 calls for the FEL PRO 9089PT (2 req'd). The L67 gasket does cost about 50% more than the L36 gasket.

Anyone know if there is any difference in the physical construction of these gaskets (L36 vs L67)? Is the L67 gasket a metal-core (vs L36 not)...perhaps even one of the new MLS gaskets FEL PRO is supposedly making now? Does the L67 gasket have some kind of sealing ring around the cylinder hole (to better seal boost)?

If the 9089PT does have some kind of advantage, any reason it wouldn't fit on an L36?

Not sure if this helps..Here'* an L67 block. As far as I know..the gaskets should identical between front and back on both L36 and L67. Unless the L36 uses a different oil passage return or something.

well its a fact that the block are the same and the head have the same casting number the only difference is the injector that are drill .so it must be the material of the gasket that better quality .but why different part number for the L36 .do they have the same thickness