The ones that arent really covered by anyone...who's brother heads are generally exploited in incorrect ways by folks spewing misinformation on what to do with them with stone dremel tool.
I'm stepping back in where I left off years ago when I started that 318 head porting thread.
There is nothing wrong using 318/273 heads on a 318/273. They are volumed accordingly for cid and work very well...which has been somewhat of a mystery because mostly folks go for the bigger Port head. No one was around to say 'hey look what this does'..
I'm catering to that crowd....ultimately factory iron is my game.
That's why.