My random 2cents:
I think the devs have done a great job with OHV ingame as far as production/stats/emissions/etc goes, the only grip I have is in rpms.
I think by late 60s early 70s there should be a little more rpm range available to ohv, but without adding additional power (IE: Taking the same calcs and simply stretching them over slightly more rpms).
I know the basis for this is in the American engines, but, even with a +8 on heads (to simulate the great experience American manufacturers had), in that era for similarly sized engines (4.6 to 5.0L), The automation equivalents could barely reach into the 5000 rpms.
Fast-forward to the mid 1980s, and with a 5.0L ohv V8 it still takes +8 or more to get it into 5000 rpms still.
It seems like after the late 50s early 60s, the Automation ohv engines don’t get any more rpms for the rest of the years. That is what bugs me.
This is just my 2 cents though, take it as you will. This topic has been beaten to death in the past, and I’m not going to defend myself in this thread, as we’re all just beating a dead cow. Same arguments as always… Same fights as always…
TL;DR - OHV needs a slight rpm stretch in later years, but we’ve all just beating a dead cow right now.