I had been using 4.15" as the head gasket bore dimension when I calculate compression ratios, but that was just a guess. I have seen people referring to a 4.39 head gasket bore. Is this the standard FelPro head gasket that I would use on a 390 or is there one that is closer to that actual cylinder bore dimension? 4.39" seems about right for a 427 cylinder (4.25"), but pretty big for a 390 at 4.05".

 

the 4.39 numbers sound right to me and are standard for the FE head gaskets, regardless of actual bore size. Give Rob McQ a call over at Blue Oval Performance (303-762-8298), he would be able to tell you if there is anything different available.

--Mike

 

Thanks Mike. I will give Rob a call.