people ask me all the time about gas mpg on my cars and it is not that bad but i never built them for it and i have had some nasty big block on the street all rollers 548 blown 572 13to1 548 14 to1 620+ 10to1 and smaller ones 477 12to1 468 12to1 460 11to1 all of them were driven on the street most of the time they idly a round town so im am not in them all the time