I had both sets of heads, SR M.W. flowed 340 @.700 and 440-1 CNC ported flowed 370 @.700 both with 76.00CC chambers and valve spring pressures on two different short blocks, the pump gas 518 C.I. motor made 50 HP more with the dash 1 heads and the 526 C.I. race gas short block made 70 HP more, I used the same intake(440-3,400-3) on both sets of heads and the same carb. on both motors I have a set of unported Victor M.W. heads on my current 400 block 505 C.I. stroker motor with a Indy 400-3 on E85 in a 2750 lbs tube chassia S/P bracket car, it has ran a best of 9.003 at 147+ mph. My message is buy the best heads now instead of wishing you had later I have a Koleno block and a set of CNC ported 440-1 with Jesel rockers on the shelf for a future build, I just bought a set of B1-MC ported with Ti valves for the Koleno block so I can build the best all out Wazzoo motor once and for all