The answer to the big block/small block question will vary by manufacturer/ year/ and even the use of the engine (car or truck) Typically, the blocks of any given manufacturer will be divided into the groups "big block" and "smallblock" The same basic blocks are usually used for several different engine sizes within the respective groups. Straight engines? As their name implies, the cylinders in a straight engine are all aligned with one another, as opposed to multiple banks of cylinders such as with V6's,V8's,V10's, ... I speak Chrysler so I'll list the big blocks and then the smallblocks BIGS Starting with the raised block engines 440 426 Wedge 426 Hemi 413 383 Golden Lion and then the Low Blocks 400 383 361 350 Small blocks 360 340 318 273 I'm guessing here, but the new 5.7 Hemi is a smallblock derivative, as were the 5.9Magnum (360) and 5.2Magnum(318) Inline 6's 170 198 225 There were also many inline sixes produced in the era preceding the overhead valve engines (mid 1950's) of which I have little interest or knowledge. I'll take a crack at the Chevy engines Bigblocks 454 427 409 396 I know I missed at least two, maybe one of the Chevy guys can jump in and help. Smallblocks 400 smallblock 350 327 307 305 283 265 I probably missed a few here too. Fords Bigblocks 460 429 428 427 372(trucks) 360(trucks) I've heard that the 351 Cleveland is a big block Small blocks 351 Windsor 302 289 The modern 5.4, 4.6 V8's are smallblocks The Ford guys will no doubt see all sorts of holes I left in their lineup.