W2 head porting observations help needed!

So, I bought, and have setup and been playing with my new flowbench, and have ran into a few curiosity's. I have a set of early, 1st design W2 heads (a buddys) that were assembled by a well known, highly reputable shop, but the engine didn't seem to run as hard as we felt it should. These have 11/32 stem 2.05 intake valves, 3 angle valve job, and on my bench the initially flowed 8 cfm LESS than a box stock speedmaster. Down 10 at .300. The bowls look very under sized in my opinion, so, I did a bowl cut, added another angle between the bottom 70° and the blending into bowl. That got me a increase from 217@ .500 to 245.6@ .500 with a peak of 253.4 @ .550