I wanted to be able to understand then duplicate or at least approach the success of the 32-36mpg Ford pickup- I too have a '60s pickup shell and several '60s V8 engines laying around and boy would I love to get
better MPG in that old pickup than I do in my Tempo!
It appears the data gathering phase is over. That's OK because what Mr. Wiseman had was made by 1977 with a lucky combination of stock components: '63 Ford pickup body and chassis, 361 Ford V8 with 2bbl carb, stock three (later four) speed manual transmission, stock wheels and perhaps stock or nearly stock-type tires, and a 2:1 axle from a car... and that's it, no special mods at all as far as fuel delivery, vehicle weight, vehicle aero, etc.
AND no special driving techniques like P&G.
The '63 was an utterly stock combo except for the rear axle ratio of 2:1, which allowed for 45mph cruise @ 700 rpm. Well, I ran into a couple of roadblocks when attempting to come up with my own 32-36mpg combo, first one being that 2:1 axle ratios
do not exist. At least, Google couldn't find me any. The lowest I was able to locate was 2.21:1, for a DANA gearset used by AMC in the '80s- OOPS, too new for a truck assembled this way by 1977. (
1982 87 AMC Jeep Dana 35 Ring Pinion 2 21 1 Gear Ratio 7 1 2 Dia 19 42 Tooth | eBay) George's truck wore all four of it's original wheels- kind of points to a Ford axle- and the lowest Ford ratio in that era was a 1970-only 2.33:1 but the source (
Ford rear ends) doesn't say what model that was for. Otherwise the lowest was the 2.47:1 from the Granada. Another bit that points toward the axle being Ford is that everything else- wheels, springs, shocks, and presumeably the driveshaft- bolted right up (that li'l car axle had the same sized u-joint yoke and wheel bolt pattern as a pickup?
). We are told the rear wheels tracked inside the front due to the narrow car axle; the narrowest Ford axle of all was the Maverick's- yes, it's even narrower than Pinto and Falcon at 56.5" wide- not enough to cause the rear wheels to completely track inside the fronts, but they would be a few inches in on each side. The lowest Maverick ratio was 2.95:1. Ahh, the mystery continues.
Anyway, even though it appears I will never be able to source a 2:1 axle, let's continue under the presumption that's what the '63 somehow had. It had the stock three-speed manual transmission at first, and this is the transmission that gave us the 36mpg figure. Later the truck got a four-speed but that would have
no effect on cruise rpms, as both transmissions have 1:1 top gear ratios, and this truck was not equipped with an overdrive.
With a 1:1 top gear and a 2:1 axle, the only unsolved variable for gearing to get 700rpm @ 45 mph is tire size. Plugging in these known variables into an automotive performance calculator (
Wallace Racing - Automotive Calculators) tells me a 43.2" diameter tire is required... Ummmm... 43.2"?!? Most common tires of the era were 25-28" diameter (
Tire Sizes and Dimensions (plain text version)) so that is quite a large discrepency. Just for reference, plugging a 27" tire into the calculator gives us 1,120rpm @45mph.
And one more thing about the axle- it had ball bearings. Bearing drag- ball or roller or ball vs roller- is considered to be so insignificant it is not even factored into performance simulations.
OK, let's set aside for the moment the unavailability of 2:1 axles and the unlikelihood of the '63 having 43.2" diameter tires on 15" wheels... yeah, let's say it had those things. It had a 45mph cruise @ 700rpm and was able to out-accelerate the hot muscle cars of the era from 50mph on up WITHOUT DOWNSHIFTING. The idle specification for the 361 was 500rpm; at 45mph it was only turning 200rpm above idle, and at 50mph it would have been at 778rpm, and at 80mph it would be 1,244rpm. Have you ever looked at a tach and gotten a feel for the difference between 500 and 700rpm? Have you floored an engine in top gear from idle speed? I don't even need a dyno chart to know these rpms are way, waaaay below peak HP and torque; in fact, at just above idle very little torque is available, then to top that off it is being fed through only a 2:1 reduction- instead of the more common 3 to 4:1- so "flooring it" would only result in the sound of intake "waaaaaaaaa" with no discernable acceleration taking place. On a closely related note, the 3,200-3,400lb truck did not enjoy a weight advantage over these cars.
Incidently, a reasonably attainable redline rpm for such an engine- 3.50" stroke, hydraulic tappets- in street trim would be about 6,300, which if obtained in top gear would send the truck hurtling down the road at 405mph. 
Clearly I would have to go with an electronic speedometer, as speedo cables twist off at about 100 mph. 
Is that because the speedo needle hits a stop and the speedo gears won't let it go any faster? 
Do we have some issues to sort out? Yes we do, and we haven't even gotten past the basic stuff yet. I can hardly wait to dig into the 200-2,000mpg stuff.
iveyjh- Is this too mean?