Mine has a 12 gallon cell so I have to keep an eye on it. 4.56 axle. Yep, pretty bad FE. This is my first low 11 sec car so nothing to compare to in my past. But I didn't build it for FE and truly don't care...just so I don't run out of gas!!! (Actually, never intended to drive it on the street but a 408 is just too happy and rambunctious to only drive at the track. At least that's what my wife tells me! I plan to have her driving it soon.)