[rdl]

Virgin 48 heads generally spec at 72cc’s, while 62 heads come in at 75cc’s. (There’s a theory that 48’s used on 350 HO’s may have been machined as small as 66cc’s — but that’s another unresolved debate). The 48 was matched to the 068, while the 62 was matched to the 067 owing to the profile and compression characteristics of the cam. Lots of threads on this topic back in the day. Rotella’s book canvasses this nicely.

[Gary H]

Originally Posted by rdl

Virgin 48 heads generally spec at 72cc’s, while 62 heads come in at 75cc’s. (There’s a theory that 48’s used on 350 HO’s may have been machined as small as 66cc’s — but that’s another unresolved debate). The 48 was matched to the 068, while the 62 was matched to the 067 owing to the profile and compression characteristics of the cam. Lots of threads on this topic back in the day. Rotella’s book canvasses this nicely.

I've actually CC'd #62 heads that came in at 78 CC's. Just did a set of #13's a couple of days that came in at 76 CC's