I purchased a set of Summit racing Vortec heads back in 2012, installed and ran until disassembly this year. I took the heads in to get a valve job and they milled them too. Now I am ready to reassemble and ordered a kit to cc my heads since the milling. They were advertised as 67cc, but now I’m getting 74-75cc. Is it possible for a simple valve job to add 7cc to the heads since the valves get recessed slightly? Called the machine shop and he said it should add anything, especially considering they were milled. This leaves the issue that it’s possible Summit shipped me 74cc heads instead of 67?! Kinda confused and looking for some feedback...thank you!