I have a flow bench, but never worked on a 235 head. I just finished up a Pontiac set of heads and did my final test. One port was just a little low so out came the grinder again. I made what looked like the right cut. Turned out not to be and it took hours of work just to get it back to where I started. Air flow is a tricky monster to tame. I have a 250 head setting on the shelf with all new parts and about 200 miles on it. I ported it and installed bigger exhaust valves. Air flow was 15% or better with minimal work. On the truck it ran great at WOT and at cruise speed. Climbing hills with your foot into, it would shake so bad it broke a motor mount and shock the air cleaners off. After a lot of trouble shooting and reading flow numbers, dad and I figured out the exhaust was out flowing the intake and during cam overlap, the exhaust was pulling the fuel mixture out of the cylinder creating a super lean condition. With a stock head and everything else the same, the engine runs flawlessly.
Joe
