Your faith in Ma Mopar’s production tolerances are completely unfounded. There’s a reason why pretty much all of the information out there says they were 65-72cc’s and mostly on the larger end of that range.
And I didn’t say they were supposed to be 65cc’s. I said the ones I have were in fact CC’d at ~65cc’s pretty much across the board for the pair and I’m fairly certain they were uncut when I got them. After some light bowl work was done after they were opened up to 2.02/1.60” valves they were closer to 66-67cc’s, which I personally verified, before having them surfaced back to 65cc’s to true them up a bit, which I also verified.
But hey, maybe I got the only pair of 308’s that were ever 65cc’s. Believe what you want, I honestly don’t give a crap. Saying every 308 head that was ever manufactured was exactly 72cc’s is just silly given the production tolerances on those heads. Certainly they weren’t all 65cc’s either, but there was definitely a fairly generous range.