What cc dome cool head for pump gas 85R?

[dansvan]

looking to purchase a cool head for my 85r on it's first overbore. What cc chamber is good for 93 octane pump gas? Should you run the stock head gasket with the cool head or the CR?

[tecate/250r RiDeR]

not sure on the on the size but i thought the cool head used o-rings!?...ive never had one so idk..

[EAT_A_450]

I would like to know both of those answers as well (which dome and which gasket). The cool head does use o-rings but the other versions like Duncan use gaskets. I have a 19cc dome and both gaskets. My jug is getting ported so I can't check it but I am curious. I also have a 69mm piston.