in chevy they make a 400 small block and a 396 big block .. . . a chevy big block is a lil longer I guess for the bigger pistons . . .. . btw I think my dad use to have a 350 in his vega . at one point he had a 454 in it . . . we also have a lil thing with a 350 in it .. that will be out and about when it's back to geather