I was looking at getting some dart cnc heads, but am tied between those, bmf cnc heads, or afr cnc heads. What heads would make the most power out of the box at 335 or 350 cc range?
I already bought my intake, so oval port isn't going to work
You still can't see how your thinking is backwards?
If you can only afford to do this once, then why would you make the MISTAKE of building an induction combination around an intake manifold?
Open your eyes.
Buy the heads you need for the combination, then the proper intake to match. A set of heads costs $2500-4000 and an intake costs from $250-400.
Can you afford to buy a set of heads to match your intake, then find they don't work as planned and sell them at a loss later to replace them with the proper cylinder head?
Sell your intake and and get the proper heads, then buy your intake later. You'll lose maybe $100 to 200 selling your intake, but you'll get a better running combination in the end.