46 to 41 rearend swap?

[vtwinsideways]

My wife has a '41 Ford pickup with a few modifications that she wants to put back to stock. I am new to post '31 Fords and need to know if there are major differences between a '46 passenger rearend assembly and that of a '41 pickup? Any info is appreciated. Thanks. Luke.

 

[ford38v8]

Luke, the differences are not formidable, but if she wants bone stock, then of course you'd want original equipment fir judging purposes. Going with the '46 assembly will move the wheels outward by 7/8" each side. The axle ratio may actually be more preferable in the '46 than as the pickup may have, as pickups were generally geared lower than passenger cars. Spring hangers are the same for both, but again, pickups would have stiffer springs than passenger cars. '41 shocks are Houdaille as are the '46 shocks, but with minor differences also. Even if you built it with all the '46 components, it would take an expert to tell the difference.

Taking this a step further, you probably have an open driveshaft in the conversion, which would have to be changed out to torque tube as original. This will require a transmission to match, which are readily available, but you see how the list can get long depending on how the truck is set up as it sits today.

 

[oldskool]

i might add that the 46 rear had a sway bar and you would need to add the 46-48 frame bracket to your 40 a worth while improvement I might add

 

[TJ]

The '41 pickup uses the same rearend as the '40 passenger car and 40 pickup. The 46 rearend is wider and also has a longer driveshaft(torquetube). If you currently have modifications that include an open drive rear end you can use the transmission from a 42-47 Ford pickup which is set up for an open drive rearend and bolts right to the flathead. It would be helpful to know the modifications that have been done to your pickup to guide you in making the changes.

 

[vtwinsideways]

Thanks for the info everyone. The truck currently has a sbc with a Saginaw 4 spd and a 55 Chevy rearend. We would like to go back as stock as possible. Luckily the frame is nearly unmolested, with the exceptions of welded on spring hangers and some small cuts to the crossmember to accommodate the saginaw and drive shaft. How much longer is the 46 torque tube? Luke

 

[alanwoodieman]

wheel base on a 40/41 pick up is 112", wheelbase on 46 is 114" so torque tube will be longer by 2" Look for a 3:78 ratio rear end out of a 40 car, most trucks came with a 4:11. trucks had a 29 tooth cluster gear, cars had a 28 tooth cluster gear, most 40 had a side shift trans, most picks up had floor shift trans. Just a few differences. Car rear axles are usually easy to find-I would bet that somewhere near you is a hot roder that might do some drivelind swapping with you, put an add on craigslist. good luck-I always like to see them go back original but driven

 

[vtwinsideways]

Thanks for the info. I'm going to pass on the '46 as a '41 donor has been located. Now I'm down to a radiator and an engine. What years do the ring and pinions swap?

 

[rotorwrench]

There are several different axle types for the narrow rear axle assemblies from 38 to 41. The six spline pinion set up is the easiest to find used but there are also differences in the tooth count between the early axle assemblies and the later ones. You will need to know what axle/spider gear tooth counts you have when looking for axles and you'll need to know thw spline count on pinions of the ring & pinion sets, either 10-spline or 6-spline. 6-spline were used from somewhere in 1939 through 1948. The axles changed about the same time. As was already mentioned 42 thru 48 axles are all longer/wider than 38 to 41 but they did have 6-spline pinions that are usable on the earlier models with 6-spline.

 

[42merc]

Thanks for the info. I'm going to pass on the '46 as a '41 donor has been located. Now I'm down to a radiator and an engine. What years do the ring and pinions swap?

If your '41 "donor" Is a passenger car, the drive shaft & torque tube will be 2" too long.