Making power out of the 318

Hemi. Full stop.

I love small blocks but they weren't performance engines "from the factory". Head flow was abysmal, They had hydraulic cans with non-adjustable valvetrain, two bolt mains, cast pistons, low compression, on and on. They were designed for reliable passenger car transportation.
You better get off your high horse and go back to school. 340 was a performance engine. Tom Hoover's name come up in the development. Was the basic engine designed from the start? No. But it wasn't used for anything other than performance is my point. The Amazing Mopar (Dodge/Plymouth) 340 V8 Engine