hi i got a 350 small block and a 454 big block i want to put of those into my 72 chevelle but dont know which one i want the big block for power and sound but i dont think im gonna be able to afford the gas my dad says we can get tons of power out of the 350 exhuast sound is really really important to me i was wondering if u guys could give me ur opinions

To get the small block to perform like a big block I don't think the gas milage will be that much different than a mild 454. Using a Q-jet on the 454 could net 14/mpg if it is a mild 454 with gearing of 3.31 or numerically lower and a low stall speed.

I would go to the dark side and go big block. :D