There are no absolutes....and there are a ton of STRONG 445's out there running with a 4.250" stroke.
But trying to bore a block just to get a magic number is most certainly not the wisest thing to do.
I had a BBM head that we did some R&D on....raised the floor, did a little SSR work, and with a 2.100" valve it got us 340 cfm with around 170cc port volume. A 2.100" valve will work with pretty much any bore size. On a 4.030" 352 bore, I could get to .800" lift before any valve/cylinder interference occurred.
This conversation could go in SO many directions...
I'm used to the BB Chev world where we work with much bigger displacements, bores, and heads but still, while
others are building 600 ci pump gas engines (4.60 x 4.5) and happy to get 700hp, we have focused on a 4" stroke combination (4.60 bore, 532ci) that makes 840hp and 720 lbs ft. at 6500/5000 respectively, hyd roller on 93 oct. "Philosophically" adding stroke, especially going over square, brings other things to the table that aren't very conducive to making power especially when rod ratio starts getting short. Making power is all about piston speed. Sure, you're going to make more power by increasing displacement, that's a given, but not at the rate you
could be if the rest of the combination was there to match. A short stroke large bore 440ci engine is a lot less demanding than a long stroke, small bore engine of the same displacement and easier to make more hp/ci and without turning a bunch of rpm. RPM is an easy way to make HP but it also brings it's challenges.
I'm going to do an experiment this winter. I'm going to build a 422 ci combination that I started to describe above; 4.11 bore (.060 over 390) 3.98 stroke, but with a 6.8 rod and about 10.5:1 CR with a Straub hyd roller. I'm either going to use a set of Edelbrocks or FElony heads. My induction systems are all designed around cross sectional areas. Port volumes, especially with an FE head (because the port is so short) really don't tell me much. The "port" starts at the valve job and ends in the plenum. Where the head and intake come together is pretty arbitrary and insignificant. I'll have to do some cross sectional measurements on the FE heads and intakes to see what I'm working with. I work around a designed minimum cross section/restriction in the port ahead of the short turn and the location of that minimum restriction is relatively critical. I know all this stuff about a BB Chev like the back of my hand, but never dove onto the FE like this. I've made 1.57, almost 1.58 hp/ci with the 4" stroke combination BB Chev. No vac pump, no crank trigger, no trick oil pan, hyd roller, pump gas, but a lot of focus on induction and valve train. I'm going to see if I can apply everything to the FE that I've learned in the last few years developing this combination. If it works, I should be looking at somewhere around 665hp and hopefully high 500 tq, like 570 or so. A lot will depend on what intake I end up with. Not many good selections in that regard.
LOL...I'm rambling on...I know...