Id be running an aftermarket block(like a dart or world) at that power level. While your at it, you might as well shoot for even more displacement. Get one of the ones with 400 mains and 400 bore. Any one of those units you spoke of with the proper heads and roller camshaft can be 600 horsepower plus capable. But, no matter whos blower you use, it wont be super efficient at real high rpm, so thats why bigger is better here........because its easier. Even if you use a stock size 400 crank. Id run at least a .040 bore, but it wouldnt hurt to stroke it up somewhere near 427 inches. That will help you to make more power at a lower rpm where the blower is still operating pretty efficiently. Id talk to Harold about a camshaft. I suppose a solid flat tappet can even do the job, a jump to a roller isnt quite a necessety to break 600 horsepower with a big blown motor, but it helps. Another thing, I feel that you oughta be able to pull it off with a real good 23 degree head. IF you wanted this power naturally aspirated, no doubt you should consider a rotated valve angle head other than 23 degrees, but I dont see an absolute necessity. Im no expert on blower motors though(well lets put it this way,,,,,,Im just plain and simple no expert hehe), so you might want to get a couple more opinions on the heads but I think a good 23 degree head will do just find. Build a 427 stroker correctly in naturally apsirated form and you can break 500 horsepower without too much effort. So, take it the next step further and strap on a supercharger and I see no reason that you cant make in excess of 600 horses without anything way too trick.
