What you are saying is what is true of any engine. Heads, induction and camshaft.
There are 300 inch comp eliminator motors that make 800 horse or thereabouts. Mopar short deck W8 deals.
Really the only variables are bore and stroke as to the limiters to the output.
To me, the big limiter with the 318 is bore size, it’s friggin tiny. It’s a block of wood under the gas pedal.