I am pulling 16-18 mpg out of mine at 65 mph on the hwy, with 26.5" tall tires, 3.21 gearing, and a stock converter. It turns about 2700 rpm at that speed. The motor is a 73 318, with stock compression replacement pistons, stock heads, Comp XE268 cam, headers, 2.5" exhaust, and a holley 600 carb on a performer intake.

The trans is a 904. I am hoping the milage might make an uptick when I move up to a looser 2-2,200 stall to complement the performance gain.

I have a fairly large cam, but that 284 is even bigger.

The relatively stock 70 340 with J heads in my 340 Formula S 69 Cuda pulls about 15-16 with 3.23s and a 2000 stalled 727. The manifold is stock and the carb is a worn out Edelbrock performer 600 cfm.

Last edited by MoparJ; 12/11/08 03:04 PM.
2016 Ram 1500 Crew Cab: 5.7, 65RFE, 4.56 gears with locker, Hemifever tuned, AFE intake, 87mm throttle body, JBA headers, 3" Flowmaster exhaust, split to dual 2.5" exits. 13.57 best ET so far.

Searching for new A or B Body Project!