I have a 512, procomp victor copy heads, around 12 to 1 comp, 1.6 rockers, .740 lift cam, Manton pushrods, hand ported in my garage, homemade intake with two AFB's for NSS, 3200 lb car ran best of 9.65 @ 140mph, dyno said 725HP nothing exotic, I think that is about the goal you set in your post. The engine ran for 10 years with one freshing, bearings and rings. Last summer it broke a rod, going back together as a 540. will see how it does in that version soon. My flow numbers on the heads at max wedge port size were close to what was posted in this thread. I bought the cheap procomps, because I did not want to screw up an expensive set porting them myself, I am pretty happy with the results per dollar spent, and reliability. I would guess a good single plane intake with a dominator would make it at least a tenth faster, maybe more.