Cheers chaps! I'm asking as there's one one ebay now advertised as 138.4, so I guess its virtually on its last skim anyway (as mine is!!)
Originally Posted by Cosworth Rallyesport
group A heads are 137.6mm and work fine.
Is this to raise compression? So potentially my head on the final skim could be done again with a good thick gasket and low-ish comp pistons and would be ok?