Yes, the 348 + 409 engine is a "Big-Block" In fact these engines share Crankshaft dimension and interchangeability with the 1964 and up "Big Block" Chevy Motor. ...you can drop a 454 crank in a 409 block for 1 big*** motor. The hood was never opened in American Graffiti most likely as "Falffa's" ride had a "modern" Big-Block, Aluminum headed motor. There are "Falffa's 55" toys (Models I think) with an opening hood with a 409 Dual Quad set up for an engine.