Modern 360 question

It's a little confusing. Short block/long block discussion has no bearing on the distance from the front to the rear of the block, but rather the degree of completion.

IME a short block is the assembled block, crank, rods, pistons, rings, pins, bearings, timing chain, and cam. A long block assembly adds fully assembled heads and valve train, harmonic balancer, front cover, oil pump, & oil pan.

When you get to the size of the block, the big block/small block discussion begins. The 360 is a small block from the LA engine family. Family members begin with the '64 - 69 273, 67 & on 318, 68 - 73 340, and the 71 & on 360. The LA engine block has been stroked out to 408 CID routinely, with some going even farther.

The Mopar big blocks with wedge type combustion chambers are referred to as the B/RB motors. The block design dates back to the late 50s. The B motor came in 350, 361, 383, and 400 CID configurations. The RB is essentially the same engine with a greater deck height that allows for longer strokes. The RB came in 383, 413, 426, and 440 CID. Of these the 383 B and the 440 RB were optional in A-bodies. The 383 from 67-69 and the 440 was a 69 only install.

The 426 Hemi was installed in a few A-bodies in 68 intended for competition. It is sufficiently different to warrant a separate discussion.