Rebuild or replace?

66fs said
Not to get into "Bench Racing" but A 360 with 250 HP would be a low rpm tractor motor. A 250 HP 273 would be a High Performance motor. The 273 would win no problem. Plus by changing motors, the OP is replacing everything in the drive train when he does not need to.

I'd build a 318 , they're cheap. Stick the 273 in the corner of the garage.
That way you dont have to update everything else. Though I might do a street convertor, like the 200 kind, while you're there...