[MARKDTN]

It's gonna be hard to get 300 HP out of those heads. A cam will help but if the heads don't flow and the exhaust is restricted and all of the other things with it then you won't get the power out. Not to mention the problems these days with flat tappet cams eating lobes. I don't do carbs anymore. I don't do flat tappets anymore. If I was going to build a 350 today for anything it would be fuel injected and I would start with a roller cam 1-piece seal block. I doubt you want to go that direction, but even the TBI 350s have more HP and torque than a carbed 350 truck engine. So you want a carb. A Q-jet is a good choice. Good driveability, lots of CFMs wide open. Nothing wrong with that. You have a nice bottom end it sounds like, but it won't do a factory roller cam. You have to decide how to best spend your money. But me (and again if I absolutely had to use a carb), I would find a 1996-1999 350 Vortec truck engine to build and put a Q-jet intake on it. There are some Vortec castings that cracked worse than others. Vortecs are generally cheap, maybe you could get a guarantee that they were good and get them cleaned and magnifluxed? No good-at least maybe you get money back on the heads? Even the pick-a-part would at least exhange them so you were only out cleaning and magniflux cost. If you do use a flat tappet cam get the right oil and follow the break in procedure to the "T"-no shortcuts. Good luck with your build.