Good morning, I just acquired a Model AA pickup, it was turned into a "yippie" as he called it- basically a farm buggy, but it has an interesting piece, a Dual high with the rocker pedal, it goes behind the 4 speed transmission in place of the intermediate shaft. My question is this- I have a 1938 "Tonner" that I drive often, is this unit tough enough, or have enough "gear" in it to get an extra 15-20 mph out of the 38? Very slightly modified 85hp, intake and headers at this time, cam soon. Any thoughts or advice are much appreciated! And any information on the Dual High!
Well while we wait for a more educated answer I'll drop this dribble, When you are at your current high speed are you powered out or are you at the highest rpm, if it just won't push it thru the wind any faster, but you could run a few more rpm without hurting the motor taller gear won't help, but if you are just tached out but still have plenty of power taller gears will equate to more mph.
That "Dual-High" is actually an underdrive to 'gear-down' for more power(roughly 30% drop as opposed to your expected 30% raise) in those under poweres/overloaded commercial vehicles from the 'day'. Your '38 'tonner' had a choice of 6.6 or 5.14 ring/pinion ratios: the "Dual-High" in the Model "AA" was usually combined with the 5.17 'worm-drive' to give enough power to 'pull' a load in low, then switch to high on the road for speed(?) & gas saving. I suggest looking for a late "AA" or "BB" 5.14 rear & spend some time on "Ford AA Truck center"/forum for more info. I don't know how well that 'Dual-High' will stand up to 'horse-power'. WARNING: those guys are mostly 'traditional' & not into 'hot-rods' ! LOL
And I do not believe there are any taller gears for the 1 ton rear- but I could be wrong! Mine has the 4:10 ratio, I am told they were available with 4:10 and 4:56.
Wow, great info-- so my 38 has either a 6.6 or 5.14? Good to know- Any info on the 41 Tonner? I have one I was going to use to convert to juice brakes. I was told by the previous owner about the 4.1 or 4.56, but I didn't ever really look into it.
Beyer: Before changing 'stuff', maybe grab a calculater & 'run' some numbers for gear ratios/tire sizes/engine rpm/desired MPH. That 85hp won't 'like' RPM for very long(especially freeway speeds that are necessary these days to keep from getting 'run-over')so you'll need to compensate with gears &/or tire size(dia: 6.50/20" are approx. 341/2" tall;6.0/20" arer321/2"; etc.), or possibly 'pass' on the "Dual-High" in favor of a "Warford"(or simular) that has a 'low'-'direct'-'over' arrangement. I tell you these things as I went through a simular process with an earlier "AA" that I'm working on. To paraphrase another HAMB contributer :"You have three choices: Fast, Cheap, or Easy, BUT you only get to pick Two of them at any given time" (Thought Josh'd appreciate the 'credits'! LOL) Also: Sometimes it helps to brainstorm 'Outside-The-Box', even if you don't actually 'go-there', because a 'better' answer may be revealed! Good Luck with the truck!
Take a look at the 41 tonner: determine the axle ratio: if it's the 5.14 it'll make the brake swap SOOO much easier(just swap the whole rear assy, torque tube & all into the older truck, & while you're at it; check the front axle for simular swap: I used '34 "BB" axles on both ends of my '28"AA" for brakes/hubs/kingpins/axle ratios/etc) Yes, I like the looks of the older truck so much better than the newer!!
Beyer : Some notes on using later axles/hubs/etc. : if you decide to use the later units you will need the Budd-type wheels that go with them(drop-center) as the hub spacing is different than the "AA" units: your 'flat-center' '31 wheels , if used with the later hubs, will position the tires directly in line with the fender edge(not good!) I wanted to use the 20" wires off my '28 "AA", but had to use the Budd wheels for this reason. The advantages of the later axles include better(stronger) axles/spindles/hubs/etc, as well as 'juice' brakes. I went further & used '99 F-350 disc brakes on my truck, but my post concerning this 'mod', even if it provided better, more reliable, & safer brakes, was considered OT & was deleted. (Yes, I tend to 'go outside the box', just sometimes I go too far outside for the 'Watchers'!) LOL!!
I will be working on the 38 in the next few days, drtrcrV-8 do you know where the ratio might be on the rear axle assy? As for the front brakes, I intend to use the spindles and hubs from the 41, but retain my 38 axle as it is transverse, vs 41 parallel. As for my front wheels, the 38 and 41 tonner have the same large 5 lug pattern to them. I am running Dunlop 7.00/20 tires on original wheels. My original intent was to run a late model Borg Warner 4 speed from an 84 F150, 4th gear is an overdrive.
Beyer : If you're lucky you could have 5.14 gears, but 6.66 could be there also; if you have 5.14, why not "swap" the complete unit, inculding torque-tube?(saves lots of time & work, ask me how I know!!) If you use the hubs/etc from the later trucks you'll also need to use the corrusponding wheels to get your tires under the fenders, at least on the front, as the later units used 'Budd'-type wheels that are 'drop-center' so the hubs are extended : the original 'flat' wheels put the tires directly under the fender edge(Of course I found out the hard way, so now I'm using the 'Budd' wheels on my '28. Also: tag on to 'ford aa truck center' website/forum section; yes, they tend to be more 'resto-original', but they know way more than me about these trucks! You are welcome to call : 707-676-0222 with questions, I MAY have answers(no guarentees!!) LOL
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