Re: how do I get better MPG?
Poor fuel economy with these old V-8's is a problem! I can remember my brothers stock '78 (in 1980) with only around 25K original miles getting around 12 m.p.g.! He always swore by that old Scout and kept it for many years. He said ride was much better than a Jeep, it was a good tow platform, carried a pair of dog cages easily, and with a little work, able to show its ass to the "CJ's" on the trails. Back to the problem. Basic stuff first.
BASICS: Good for 1-2 extra MPG.
1) For road use, run high tire pressures, at least 30 PSI. Run a smaller radial tire on the road and swap for larger ones on trails.
2) Insure the brakes are in good order and do not drag.
3) Insure the bearings are in good order/repack. Insure trans/diff fluids are fresh. Run lower weight oil, 10W30 or less, no 20W50.
4) Drive slower, try to stay around 60 MPH or so! parasitic drag above 40 MPH hurts! Smooth throttle inputs.
5) Make sure all the original vacuum hoses, pollution device hoses, etc. are in good order.
SPECIFICS: Also good for an extra 1-2 MPG.
1) Since this is a daily driver, you need 3.54 or so gears, check the line sheet or rear diff tag to see what yours has.
2) The 4 sp. manual is a little more efficient. On the 727 auto, change the fluid/filter and insure it operates properly, firm shifts, no slippage
3) Install a high flow cat if originally fitted with a 70's vintage pellet varity that was prone to clogging. Install free flow exhaust.
4) Check the right side exhaust manifold for the butterfly valve assembly, and oil it and make sure it is operational (moves freely). If rusted shut this alone can cause the loss of a few MPG.
I am sure there are other tips, but this should get you started. I have yet to swap the ignition, but I am considering it. I do not think the electric fan is worth the effort, insure the stock clutch fan is in working order. Remember, this rig is built for years of toil, not great MPG! The old 345 is a durable mill that will run over 300K if properly maintained, that alone should be worth the loss of a few MPG! It has a factory forged crank, rod, pistons, and timing gears. My '79 with the 345 and 4sp. close ratio trans now gets 15 MPG on the road with these mods (It used to get 10 MPG or so). Recent 31" AT tires hurt a little, now 14 MPG, but they look great and work well off road. Scouts lead the way! Good luck!
Steve Mcqueen fan.