70o hp out of standard port Victors? No way. I am no expert with those heads but have used them. I built a 471 11.4 comp, 269 @ .050" .752" single pattern and mufflers we made 717 hp and 652 ft/lbs on our SF-902. Down in Ohio @ the EMC '09 with way too much timing and through 13' of 3.5" mufflers and pipe we made 695 hp in the warmups. The article on this engine just came out, here's the link. 471 700hp build