Cometic Headgasket
 

I'm going to be running 75.5mm Vitara pistons. Most of the cometic headgaskets I see for my engine are 75.5mm bore, this is the correct bore for 75.5mm pistons right or do I need 76mm gasket? I noticed these gaskets are available in 75.5mm, 76mm, 77mm, 78mm,and 79mm, does this mean someone with stock 75mm pistons cannot use a cometic headgasket?