Sorry ... I was referring to the rear differential. How to upgrade the rear differential to TRANSFER the higher HP to the wheels, not produce it.
The dressed blueprint engine which has my eye is the 383 stroker which is rated at 425HP/430 ft/lbs. I thought that was quite a lot!
... I don't want to spin the rear-end out of it, but I've had it perform with the 283 quite well (smoked the tires from a down shift 3 to 2 at 40ish mph back when it had a manual)
LOL ... yeah, no replacement for displacement.