Brownie X2!!!

[RLDSL]

I cant read the code on the second, but that 41 m1 is OLD! , that critter could be anywhere from late 30s to late 40s manufacture. Nothing wrong with it they were built like tanks. The gear ratios on the 41 are a bit different than what you would find on most 3 speed brownies as it doesnt have a deep reduction Under drive, it has what is calld a medium low that allows you to evenly split the brownie, 1-2-3, then shift the main box instead of 2-3 then the main on a regular 3 speed brownie with a deep reduction, but you do not have the advantage of the extra crawler range for heavy pulling, you just get one gear below first, but you do get the ability to split each gear three ways instead of just two which would give you immense flexibility in the mountains with a heavy load as you would only have to let fall about 200 rpms and you could drop another partial gear to keep the engine in its power range

I do have some partial specs on that box

 

[Matrix37495]

Your plan is what i want to do to my 85 crew cab. My idi is getting awfully tired. I think i'm going to make it into and offroad toy once the cummins swap is all up and going...

 

[BrandonMag]

Yeah, the fuel mileage situation is a little frustrating to deal with because I thought I did everything I should have when I put this truck together. When I originally installed the Moose pump, I was blowing smoke everywhere and I couldn't keep the pyro under 1200* if I did more than breathe on the go pedal. A little tweaking here and there (one of the things I did was turn my Moose pump DOWN two flats) and I can drive fairly normally, but I still get crappy mileage.

Next on the list is changing the rear diff. oil, maybe that'll help. AFAIK, it's original.

 

[Exekiel69]

Now that is a good find, and yes behind a cummins (low end torque) it would make a very good tow rig.
There will always be parts for IDI's, I have a few cummins and still keep a good idi, wouldn't replace it with anything.

 

[MIDNIGHT RIDER]

Please keep the IDI? We're steadily losing numbers, we need these trucks up and running or they will discontinue the parts and support.

I kept my 6.9 IDI; it's still hooked to the chain-hoist that un-loaded it off the back of my Cumminized F-350 some six or more years ago.

Some day, twenty or so years from now, maybe I will freshen it up and use it to power something.