I went through a 541(4.375 x 4.500) that was built from a Mega Block several years ago.
Flat tops(12:1-ish), -1 heads, roller cam with 1.5 rockers.
I ported the heads and installed 2.25” intakes.

Made a little over 800hp with a 440-2/adapter and an 1150 on it.

With a ported Indy TR and 2 x 1050’s it made 848hp.

With the 4.375” bore It could be built out of a stock 440 block, but at that power level I’m not sure how wise that would be.

68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads