Not really sure, the heads had a fresh mill and the block had a fresh deck. Heads went to .008 and block went down .020. They were on my last engine adn didnt leak a drop. I have a little more cam this time and Im .040 over, last time was .030. Really dont know what the deal was. I know they sure as hell wont blow out due to cyl knock, they just didnt wanna play the seal up game. Some guys will double stack them to make them seal, there is a kit out that comes with 1 set and some weird gooey 3M stuff to make them seal but I didnt wanna use that.

The RJC Head Gasket Kit will support the cylinder pressure required to get a full weight stock block Turbo Buick easily into the nines.

Kit comes complete with 2 Genuine RJC Stainless steel shim head gaskets, one tube of GE silicon sealer, special roller applicator, card board stenciling plate to apply the silicone and highly detailed instructions. Please specify thickness of gasket when ordering. (Sorry, only on thickness is available now)
http://www.rjcracing.com/RJC_Buick_P...it/hg_kit3.JPG
Just saw its no linger available. They quit making the gaskets last year. Maybe that was a hint I should followed.

 

Ive been using cometics. No problems so far.

 

I was going to go cometic, did a little reading up on the Buick boards and the FelPro 9144PTs are holding up good and are $30 less per side. Going to go with them for now. We'll see what happens