Just remembered.
Why not use the newer cast iron 12 port head from a newer Chevy pick up?
I heard the last year was 1997?
But I heard it is limited to about 500HP, more than that it starts to crack.Thin casting.
I do not know much about that cylinder head,but I assume it flows a lot better than the siamesed ports of the older engines.
Never heard of having a mix match of ports for better turbulence.When there is a mismatch,it will make the intake port to act smaller than it really is.But If they say it works better???
As far as polishing, not necessary, it's really just for looks(for cosmetics)It is not really needed,unless there is an obstruction or things of that nature.
One more thing, are you going to turbocharge your inline 6?
If so,,, you can open up your intake ports more because your turbo will be forcing air/fuel into your engine where intake port velosity is not as important as a normally aspirated engine.
MBHD
