A b8g block is always worse on gas because the bore and stroke are bigger. A 305 with a perf cam and fuel 8njection will move a lifted 4x4 pretty good. I've done it on 44s.Thanks for clearing that up. I wasn't aware that a 454 was a bigger engine than a 350. It takes a lot more throttle to get a small block truck moving, so the difference usually isn't that great. If you are bashing around with your foot to the floor, then yeah the 454 is going to use a lot more gas. A fuel injected truck with OD and stock tires will get closer to 12 mpg, not 8, which is about what a small block truck gets. This has been covered before, more than once.