AMC 258 i6 / 4.2l can get pretty good mileage but "everthing" and to be correct and working well. Good to know the axle gears, along with the ??tire size, and the
Transmission and what gear ratios. The jeep has to match the
Transmission gears, axles gears, and tires size so the rpms are in the proper range.
Transmission Gears, Axle Gears and large tires not combined correctly, like using the 2.73 gears with 33 tires.
Jeep Mileage for the 70s and 80s jeeps;
Poor Set up 9-10 mpg Hwy
Ok set up 15
Good set up 18-19
VG set up 21-24
When we talk about mileage this is HWY mileage. Stop & go and town driving cannot be used for this promo. My
CJ7 can get 23/24 HWY mpg range if I stay out of the pedal, try to keep rpms about 2200-2500. In the past I used vacuum...... gauge on the manifold to help teach me . The higer you can keep the vacuum level driving down the HYW the higher your mpg will be. When the vac is HIGH the throttle plates are almost closed and do not pass much fuel. Want to learn more... use a 6-8 vac hose and put the gauge in the passenger seat and go for a ride. The gauge reading will teach you how to drive.
In the early 70s I drove a Jeep Truck with a
AMC 258 i6 / 4.2l 3 speed..... GREAT TRUCK. It got 23 mpg back then.
The CJ (ligher) borla headers, better weber carb, MSD Ignition, upgraded plug wires, TeamRush, a better set up for engine. This is a very good set up and drives like a new truck. It also gets great mileage...... 17/18 normal and 23/24 Hwy Mpg.
Carb, intake, exhaust, gears/tires, Header?, ignition, WATER Jacket Intake, coil, plug gap, autolite plugs, set up correctly can make a big difference for the collector jeeps.
