Plenty of 318s came with four barrel carburetors. Any reason you cannot run one? IMO, regardless of camshaft duration, you'll never reach 300 HP with a two barrel.
my friend at the drag way raced this truck in stock eliminator with 318 4bbl. In the mid 90's he was class record 4 years straight with it. Weighed over 4010 lbs with driver
He ended up going 360 in both his trucks in stock eliminator. This is his other truck with 360. This truck went a best of 11.38 @ 115 mph. When he is racing class, he has another hood class legal.