The correct approach to a classic car engine rebuild starts with measurement, not parts ordering. The parts you need depend on what the measurement tells you, and the measurement often tells you something different from what you expect.

Measure the cylinder bores with a dial bore gauge at multiple depths and orientations. Compare to factory specs. Out-of-round or taper beyond the specified limit requires boring and new pistons. Measure the crankshaft journals in multiple planes. Compare to the minimum serviceable size and the bearing clearance specifications.

Only after measurement do you know whether the block needs boring, whether the crank needs grinding, whether the heads need resurfacing. Ordering a rebuild kit before measuring is putting the cart before the horse and results in either not enough parts or unnecessary spending.