300 HP out of a 318, is it possible with bolt ons?

I don't have any numbers for comparison but I took a fresh .030 over stock 318 that I pulled out of a Dodge Aspen wagon, purchased from an insurance company salvage auction and dropped it into a 1970 Dart GT, drove it like that, with the 2 bbl and original 1970 points ignition until it popped a head gasket. Then I put on a pair of 340J heads and matching cast iron intake with a big old thermoquad of unknown origin. If that thing didn't make 300 hp, it had to be damn close, night and day difference, even with stock exhaust manifolds it still went like a raped ape!