Just traveled on a 2400 mile round trip (MSA) Filled up 8 times and kept her around 2800-rpm (80-MPH average) and got about 26-MPG (about 365 miles per tank) Now this obviously has to be estimated because I don't run the tank completely dry and have a pretty good idea of how many more miles I can get from the remainder of the tank, before filling her up again. And not knowing when the next decently priced gas station would be on the trip, and had to refill before she hit (E). Around town, if I keep my foot off the firewall, which is harder than it sounds, I'd have to say about 20'ish. Oh ya, Stock L24, Stock 73' E-88 head, triple 40DCOE Webers on a Cannon Long manifold, stage 2 cam, 6 into1 header, Mallory Unilite dist. and MSD 6A with Mallory ProMaster coil. And local gas prices are at $3.60 a gallon