Funny that 600+HP is not considered possible when we already did it...also funny that when we first started tuning the 393, I was beside myself that we didn't make 600 right away...I had to tune my *** off to get 606HP! It was not easy, and had I put more compression, more cam, and a vac. pump in this thing, 650HP would most likely not been realized! But 606 for an engine with a head on it that has min. X section of 2.2 is DAMN good! We used every bit of the port area to get this power and I didn't even do much of anything to the intake manifold. This was a test of what could be had easily, without a ton of $$$ (even though it was still expensive) with the iron heads...This effort with Indy W2 heads would yield 75HP more and cost only about 1500. more. I can't wait to see TF's second offering for the little mopar!!