More Connecting Rod Length Theory Questions

drtybttr I'm also trying to learn as much about performance engines as I can but I don't think you'll get an true answer to this question unless you own a dyno.
Long rods benefits, longer dewell at TDC for better combustion, less piston sideload, lighter pistons and more stable at high RPM.
Short rods benefits, the only one I've ever heard is piston moves away from TDC at a faster speed creating a better intake charge can handle bigger ports than long rods for same application.

Most builder agree the benefits long rods out weight short rods and Mother Mopar seems to agree also long rod short stroke big bore seem to be their recipe for an performance engine but if want further info I'd check out 383 Chevy builds they have 3 popular rod combos for the same engine 5.565", 5.7" and 6". Just remember if you built an 383 with an Eddy RPM kit (heads/intake/cam/carb) and tried all 3 rod combo and say 5.565 rod produced the best numbers and curve all that would prove that was the best rod for this combo in your OP you stated "if every thing being equal" but to have fair comparison you have to optimise every thing to work with each rod combo thats the problem with most dyno compairson.