Here you go, Piston area and force.
Bewy, hint, to prove us wrong, All you have to prove is for same displacement the bigger piston engine generally has less psi and less psi generally by the percentage difference between the piston area. And not by some old science book but actual examples of automotive engineers or text saying it.
In the 383 B vs RB, 4.25" vs 4.03" that would be like 1000 vs 1100 psi which is a fairly big difference especially when a 1000 psi is considered average car and 1500 psi decent race engine and 1600/1700 psi is Pro Stock.
If that was the case any engine class with a cubic inch rule, they would probably run severely under square engines to make 100's of extra psi.
If you can provide real proof of this average psi loss and not some dog turd and a garden hose I'd listen to you, anything short of that you ain't proving anything wrong.
But if it is reasonable that both engines can make similar psi then you are wrong, and if a 1000 psi is considered around what the average passenger car engine makes from a 1l to 7l + no matter there bore and stroke ratios I don't think your gonna find such proof.