Just thought Id answer Number_2's question.
GM is pretty much the only one that uses engine code, or sorts anyway. They arent designation like Nissan or Honda uses.
here you go
its really more like a generation or style of the block. Just like honda has d series/b series/ h series/f series.......
Yes they are gernally bigger than the small block counterparts. A new 7L LS7 block is still smaller than the older BBC like the 454 etc....
There is the typcical SBC chevy, which comes in 3 generations. The standard one that was around since the muscle car days, that was GEN I, GEN II is the LT1/4, GEN III is the LSX motors. For the most part, parts dont mix between the 3 of them, they are sorta like in design, but the LSX is really different, its more akin to a SBF/BBC in port layout.
BBC share nothing alike with the SBC cept its a motor. BBC also came in generations, I think they are upto the Mark VIII generation. I couldnt tell you the different between the years though
Chevy
SBC GEN I 283/302/305/327/350/400
BBC 396/427/454/502
Theres the typical SBF, 289/302/351w alot of parts interchange with in the series. Theres the FE(BBF) series which is the 390/429/460 motors. Then theres the 302c/351c which were the Boss motors with 4 bolt main caps in the 3 center mains. Then there was the 351/400m motor for quite a # of years.
Dont ask me about dodge, their shit still confuses me at times.
But to break it down, dont go buy liters, just go by physical size
As covered in Spectacles Thread