48 fi pickup with a dana 41 rear end

kustomotors

Junior Member
I was told that 1956/57 Mercury wagon rear axle would fit under my truck, I found one with 3.92 with gears 42/12. Would this help out on the freeway. Thanks for any help. BOB
 
I can't say for sure that a Mercury differential will fit under your 48 F-1, or what was even used in them, but it may work. I do know that the early F1's used the Dana 41 and different ratios were available. If your differential is otherwise good you may be able to find another gear set with a different/better ratio. Without knowing what your current ratio is it will be hard to predict if a 3.92 ratio will be of any benefit.

My 46 1/2 ton had a Dana 41 of 4.27 ratio under it instead of the original banjo. That differential had some serious issues, so I acquired a Dana 44 from a 1956 F-1 with 3.73 gears and it was an easy, no problem switch that does give better speed on the highway and I'm getting 16 mpg highway. There are lots of Dana 44's around so parts should be easy to find, possibly much easier than for the 41's and may be a viable solution for you.
 
I have a original 3:92 on my 50 f1, with a built up flathead and had to take out the original 3 speed and put in a t5. Now 65-70 is no problem. The 3 speed and rear just made too much whine, would not do the engine justice. sometimes wish I HAD 3:73 REAR.
 
This has been discussed before and I think a 1/2 ton rear end up into the 70's is pretty much a bolt in swap.
Lots of different ratios and the wheels are the same as your '48.
You should be able to find more details with a search.
 
I used a 56 F-100 rear end in my 49 F-1 with 6 cylinder. 3.73 gear works, great. Before change it had a 4.27 and engine was pretty busy at speed.
 
I also put a 56 3.73 F100 end into my 49 F1 which was a 4.27. Straight swap. Banjo housing looks slightly different. Much better at highway speeds. Now I'm thinking about a 3.5 ...
 
Passenger car rear ends have a different wheel bolt pattern than the PU. Any 9" rear from 57-72 will fit with a little work.

To keep it more original, I would find a dana 44 as mentioned above.
 
49 thru 51 Mercury cars had the 5 X 5.5 wheel bolt pattern. All early 48 thru 49 F1s had the Dana 41 and Mercury used them thru 49 & early 50. The difference is the spring pad location but modification is not difficult. 1950 thru 1956 F1/F100 pickups used the Dana 44 and many 50 model Mercs thru 1951 used them also. Later Mercs changed to smaller wheel pattern used on Ford cars and axles might be interchanged but I'm not sure of this.

The Dana 44 has a 44 casting mark on the right lower rear of the aft center housing just below the axle housing bulls eye. Dana 41s have the round cover cap. Any Dana 44 from a 50 to 56 Ford pick up can be made to fit but some pad work might be necessary. New gear sets are still available for the Dana 44 since they were used for such a long time in Fords, Jeeps, and a few other models.
 
... Any Dana 44 from a 50 to 56 Ford pick up can be made to fit but some pad work might be necessary. New gear sets are still available for the Dana 44 since they were used for such a long time in Fords, Jeeps, and a few other models.

The early Dana 44's in Fords use relatively unique side gears and axles (spline count), which makes fitting different R&P gearsets involved (with ratios less than 3.73, a different carrier is used, incompatible with the original side gears). Randy's knows how to do it, tho, and sells the parts. http://www.ringpinion.com/

Bob, What ratio is in the truck now? Standard ratios in 48-50 F-1's was 3.73, from 51-on it was 3.92. Optional ratios in F-1's 48-52 were 4.27. A ratio around 3.50 is about ideal for modern driving. That was the standard ratio for the 9" axles in '57-'72 F-100's.
 
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