my 68 Crewcab gets 14-16 running empty at 50-55 with 4.10's. (4x4)
When I first bought it, it got 2 1/2 MPG. It had a tired old 360 (2 barrel) that needed a tune up, clutch slipping, with a 14' overhead camper (HEAVY).
Did the tune up (plugs, wires, cap, rotor, points, condenser, air filter) and changed the clutch. Bumped the mileage to 5.
Bought an electronic ignition conversion kit (Mallory Unilite), put it in and got 7 to 8 mpg.
Put a fresh 390 in (slightly warmed up) with an Edlebrock 4BBL and averaged 10. IF I keep my size 13 outta the secondaries!
All of the above was with the camper on it.
Pulled the camper out, and it runs 14-16 consistantly, provided I can hold the speed down. If I get up on the Interstate, the mileage drops to about 9.
When in doubt, hit the gas. It may not be the right answer, but at least it ends the suspense!!
The only substitute for Cubic Inches, is Cubic Money!
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