Hambiskit,
265: 3.750 bore x 3.00 stroke
283: 3.875 bore x 3.00 stroke
307: 3.875 bore x 3.25 stroke
302: 4.00 bore x 3.00 stroke
327: 4.00 bore x 3.25 stroke
350: 4.00 bore x 3.48 stroke
400: 4.125 bore x 3.75.stroke
Note that the 307 and 327 have the same stroke. If you put a 307 crank in a 350 block you get a 327. Doing this requires 327 pistons because wrist pin location is different.
joker51,
All the first generation small blocks are dimensionally the same EXTERNALLY. That means you can pretty much bolt one in place of another regardless of year, displacement, etc. Also, heads and intakes can be interchanged from one engine to another. The exception is the 1955 - 1957 blocks which do not have the motor mount bolt holes on the side of the block. The 1955's do not have an oil filter. Some of the later 70's engines do not have the holes drilled & tapped in the front for the '55 - '57 style mounts, but the bosses are there and can be drilled / tapped. Internally, different bores all require different pistons; different strokes require different cranks; rods are the same length except for the 400; 1967 & later blocks & cranks have a larger main journal than earlier ones.
To answer your original question, yes you could destroke and sleeve a 350 down to a 283 and you can bore & stroke a 283 up to 350, but the cost would be prohibitive.
