Chevy small block V8's-
-265
-283
-302 (used in Trans-Am racing only, not a normal production car displacement)
-305
-307
-327
-350
-383 (not a factory displacement, comes from using a turned down 400 crank and rods in a bored 350 block)
-400 (has siamese cylinders, and cooling issues from lack of water jackets between cylinders)
Chevy big block V8's-
-396
-402
-409
-427
-454
-496
-502
*I may be missing some early displacements from the 50's and early 60's, smaller than the 283. My mind is always foggy on those.
Big blocks are easy to identify. The exhaust ports are evenly spaced along the head. Small blocks have the middle 2 exhaust ports next to each other and the front/rear ports farther away from the center 2.