Mopar Action On-line – Tech Questions
kent goodall, paola, KS, 1986 dodge pickup 383
I have a 1986 dodge pickup with a 383 bored 0.030″ over,and a 727 trans. The trans, driveshaft, and 8-3/4″ rear are out of a 77Cordoba. The rear diff has 3.23 gears. My question is what would be thebetter gears for fuel mileage. Not only has the engine been bored it has aRV cam and a Edelbrock carb. and 1.5″ in. headers. Love the mag. my youngestis 13 and starting to ask questions about cars.
Kent, frankly, it is never gonna get great fuel mileage! The axle ratio youhave now (3.23:1) is probably about perfect, esp. with the large tires thatyour pickup probably has. If you do lots of 80+ MPH driving, then a swap to2.94 would be a bit better, but the payback period would be pn the order of5-10 years!
Pay attention to details for better fuel economy. Light synthetic oil, tighttorque converter, lots of spark advance under light throttle (50 degreesBTDC, minimum!), low-restriction air cleaner, leanest jets or metering rodsin carb, yada, yada.
I’m curious about that 1977 Cordoba 8-3/4″ rear axle assembly….seeing ashow 1974 was the last year for 8-3/4s! Fine Corinthian leather…sure.8-3/4″ axle, no way, Jose!