The Stovebolt Site Forums The Shop Area The HiPo Shop 1939 Chev 1 ton COE - rear end options?

THIS PROJECT MAY DRIVE ME TO THE FUNNY FARM BEFORE I'M DONE

I need some good advice.

I don't know were to start on this project, I seem to be going round & round & coming up with nothing?

Here is what it was, a 1939 Chev 1 ton COE tow truck, (no boom) shorty 108" wheel base. (Cute little bugger)

OK, I found a 1980 GMC 1 ton step van P30 chassis with front suspension, so far just what I wanted. But no motor/trans, or rearend.

I need to say at this point that my plans are to build this as a 1 ton ratrod/hotrod, air bagged & slammed right on the ground daily driver. I just picked up my air bags for the front, probably not ready for them but the price was right so I will be attempting to put them in place of the springs next week.

I can't determine what rear end will fit inside my back fenders with duel wheels "OR" deep single wheels with wide tires & has the gear ratio I think I want, 350's or 370's? Every one says that a dually rearend from a flat bed or wide step van will be the narrowest rearend. Probably one just like the one that came off this frame. (Just my luck), the rearend was gone when I purchased my frame. I found a rearend today that measures 64" across. Adding stock 16" steel dual wheels & tires will still put the tires out side the fenders about 2". So it seems I will need to go with single wheels in back. No big deal, they can be deep & that will look good to.

Inside fenders are 80". Rearend is 64", leaving 16" left for wheels/tire., 8" on each side minus 1 inch =7" for good clearance. Am I thinking right or wrong? The best gear ratio I have found is 373 gears, but I really wanted around 355 gears.

I don't know if I'm thinking wrong, or going about it all wrong. My cab & bed are not on the frame, I planned on getting the suspension together first, air bags & all, so I would know how low to set the cab on the frame to get the cab as low as possible.

I need good advice...

373's will run your truck with decent gas mileage with the right motor/ trans combo

Here's a handy gear calculator to figure what ratio will suit your engine, tires, and desired road speed.
http://www.onlineconversion.com/bigger_tires.htm

You will be pushing a lot of air even though its lowered. Don't under gear it so the engine has to work all the time just to keep it going. What engine are going to run? what transmission? With the right hp, a overdrive trans will solve a lot of gear ratio problems. You can probably find 4.10 through 4.56 pretty easy and with a decent tire hight and overdrive, they would work out great. Good low speed power, yet easy driving out on the road.

Axles of this size should be of the eight bolt lug pattern, you sure you can find the wheels you like with that bolt pattern?

Joe

Hi all;
373 gears are what I thought I would start with, since I don't have a motor/trans decision yet. Rear end must be 8 lug, & under 64" wide. It has been hard to find the three combinations so far.

My plans are, getting the frame on 4 wheels. Air bagged, than get my cab sat in place before I choose a motor/trans.
Reason is, my cab will be on hinges, "tilt cab". so i think??? what I want is to get the cab on a hinged cab frame/sub frame, in place with steering column & brakes all in & functioning allowing cab to tilt, first. By then I will have a more clear idea of the rest of drive train???
Joe; At this time I don't see a problem with wheels? I want the 50s/60s look, so i probably will be using a standard vintage dully steel front wheels? Chromed or painted black/red or? It seems that there is lots of room under these fenders for tires. This P30 front axle is the same width as the original 39 axle. For looks I will be wanting the tallest /largest tires that fit in the fenders, allowing the bottom of the running boards to sit right on the ground when bags are deflated. My air bags should pick it up 5+".

Grigg; I will be reading that web site for a better understanding of what combinations of power/gears & wheels will work for my truck. Thanks

I find that my best made plans are usually backwards from what gives best results. So I really appreciate ideas & info that others have that can get me back on track when my thinking leads me astray from reality...

A 14 bolt axle from a dual wheel cab and chassis (without a pickup truck bed) has approximate 63.5" Wheel Mounting Surface to WMS measurement, and it's 8 lug.

https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=686189&page=1

Grigg

I found a rear end. It's a ford, (late 80's/early 90's) (splicer 50 I think it is called?), full floater, 3.54 gears, @ 66" width. I think this will work. But I will need to move the spring pads in, & move the shock mounts to the rear.

Does any one have any thoughts about this rear end for my application. It is wider than I wanted, but I plan on widening my bed & changing rear fenders, so I guess the width will be ok?
I will also need to use ford wheels in rear, or cutting the center hub hole in rims to match the bigger center hub on ford axle.

Did you look at any 14 bolts?
That ford axle sounds like more trouble than its worth.