Looking for some help with this one, I've read a few posts here and I am still not very certain. Currently my 455 has a 75 block and 70 heads with the Fel-Pro Blue head gasket. Gasket is .041 Thick. My pistons sit .010 below deck. I would like to find a gasket that is around .030 thick and I can't use the steel head gasket because of the coolant passage differences between my heads and my block. Does anybody know what would work? Gasket pictures online appear to all look the same so it's hard to tell and my setup is a bit oddball. Thank you
Cometic gaskets are layered and have a variety of thicknesses available. Call TA Performance. The Fel-Pro should be fine as is, and provides a safe blow through without harming pistons if detonation occurs. Hardley worth all the work to reduce your quench .010.
Thanks guys, I'll check out Cometic. I'll be pulling the heads in the future for some porting and wanted to update the gasket while the rest of the work was being done.
With the Cometic you need a particular finish on the surfaces,...nowhere near as forgiving as felpro,....so keep that in mind
Thanks Hugger, the block and heads both had material removed from it this past winter to get to their current condition. Thanks for the info.
What Ethan was saying is both the block and head needs a very particular finish to surface.......needs to be smoother finish on the metal.......to get it seal. Your standard cutting of the block and head isn't compatible. I believe they call it rms or rma????. But honestly you won't see any real gain. There should be no issue with newer block....73 and up using earlier heads as far as coolant passage. Now going the other way......newer heads on older blocks will leave a passage in the head not covered by the block
From cometic: SURFACE FINISHING WHAT SURFACE FINISH IS REQUIRED TO US AN MLS HEAD GASKET? A surface finish of 50 RA (roughness average) or finer, is recommended for a proper gasket seal. Anything rougher may conflict with the gasket design.
Ok thanks Ben, so it appears to be more detailed than I had thought. I just had material removed from to block to nearly deck it and a .015 cleanup cut on both heads. The reason I believed I couldn't use a steel head gasket on this setup is based off what was on Greg Gesslers website. 1967 thru early 1972 head castings can be installed on late 1972 thru 1976 blocks. Just be sure NOT to use the steel shim head gasket Late 1972 thru 1974 heads can be installed on 1970 thru early 1972 blocks, IF the center two, round coolant passages are plugged in the head. I had ran across that info in this post when doing research https://www.v8buick.com/index.php?threads/can-i-use-any-455-block-with-72-stage-1-heads.195895/ The info in this post appears to contradict that. I have a 75 block and 70 heads and was looking for an alternative for the steel head gasket since I didn't think I could use it.
This is just some planning for when I do remove the heads for an update here in the near future. From the pictures on the TA website, they do appear to be slightly different (Felpro and Steel)
