Do you remember the saying what comes first the chicken or the egg.
This is what the port argument is about.
To make power you need air and fuel, the port needs to work equally well on both aspects.
I have found the HP level you want dictates the port you need.
A stock port is not good for much, this is why Kay Sissel made the ingenious Bump Port. It helped the velocity and direction of air flow to the back of the valve, therefore more air flow. This arrangement worked to a point of about 400 to 500 HP. On a race engine. If this is your goal use a Bump Port. But at this HP level the undivided port starts to show fuel distribution problems.
If you want to make more HP. You must switch to a Kirby Sissel 12 port the best bolt on head on the market ever. All the older versions of a 12 port were not any good in comparison to Mike's head.
Back in 1985 I had a bump port head with my turbo worked great until I tried to make over 500 HP. Then all my issues started, Cylinder #1 and #6 would run lean and could not fix them without making all others too rich. I stuck with the stock head way too long trying to fix the problem, to no benefit. I divided the stock ports but had to up the boost to compensate for the poor flow, it just made too much heat to try and control. Even tried a 12 port from Brazil GM had made, just too small of ports like my divided head, worked a little better but not enough to make good power.
Finally bit the bullet and ordered the Kirby head, wished I had done it 20 years ago.
P.S. Back in 1965 we raced a 292 gasser that ran good for it's time with a Hilborn Injector and a divided head not a lot HP as today, but did that baby hit a note !
Just ask anyone today what would happen if you cut the dividers out of a chevy head and they would look at you as if you were nuts, people tried it in the early 60's just ask some old guys.
It does not matter if you use a carb or injection, it's just the injection is so precise it shows up more as a driveability issue.
