i have some 862s (stock) i wanted to put them on my ls1 and anyone know how thick does the head gaskets need to be

 

The MLS gasket is about .051 thick and that should put you around 10.8-10.9. the older graphit gasket around 11.0. I just finished my LS1 rebuild and will be using my stock 862 heads off my 5.3 and the cam in my sig. Will see what happens.