· 2JZ Mk2
I can't see why you would need any plate to cut an oring groove in the deck. We have all kinds of oring grooves (non-engine stuff) machined at work and they are cut with a normal mill cutter on an NC machine usually. I'm pretty sure o-ringed engines just use a stainless wire for a groove around the combustion chamber with a copper gasket. The water and oil passages are sealed by the HG alone from what I've seen. The only issue I can see on a M engine is that the cylinder bores are mightly close together. I can't really see a need for this since a $120 MHG will more than seal the power 99.999999999% of the people make on a 7M.