I really couldn't tell you how much it will cost..... a lot depends on what we find when we open them up...... I will however keep a tally on cost of all parts and whatever labor is accumulated from machine shop work etc, etc....

Any guess on cost?

My engine builder uses Fel-Pro.
Is Cometic that much better - why??

I am not sure of the technical reasons of why Cometic work better, I can only say I have never heard of any failures with them. They are a laminate gasket, made up of a few thin layers to make up 1 gasket, like plywood. The thin layers are made of some type of metal. They have no fire ring as do felpros. Everyone has heard or had Felpros fail at one time or other, especially for blown engines. With the present choices of headgaskets available, I know I will never use any other type of gasket.