Scream'n 318 ?

Agreed, a 340 is only 7% bigger than a 318 basically has to turnabout 7% higher for same hp.
6050 rpm 340 = 6500 rpm 318.
Can you prove this? Besides calculators.
Have you been there and done that? Just wondering if your spitballing here with the aid of calculators.

A 60 thou over 318/328 ain't too far off a 340 especially in the 350-450 hp range and even better if they can take a 4 inch bore for a 333. The only real problem with the 318 is dodge also made abundant of 360's too. But still doesn't stop the 318's from being a very capable engines,
What I like about the 318 is it is not actually a bad engine for performance, it’s just cubically challenged. Therefore limited. It’ll do fine in the street. I do like that some have gone to a 4.00 bore. That’s nice!