Dear Guys...I have a '69 Beaumont with a truck 454, and TH 400. The car is well tuned up and has no gasoline leaks anwhere. Calculations ( rpm calculators, and turning wheel with cover plate removed from rear pumpkin ) indicate 3:55 rear. I am getting about 5.5 mpg with this car, driving very conservtively. My mechanic, and some enthusiasts have advised me that this is about right. I have had other muscle cars, 396/325, LS 6 crate motor Chevelle 425 hp, and a '68 Coronet 440 ( can I say that here? ) and this is still by far the worst gas mileage I have ever had. I am wondering if I should be looking at a compression test or experience slippage somewhere in the new torque converter for the answer. Oh, by the way, the car runs well. Is this gas mileage acceptable for conservatiive driving? Opinions please. Thanks in advance. R.B.