Yes - 1954 3100's had a 3.90 rear end.

Someone check my math ...

A 3.90 rear end will push your truck about 5% faster than a 4.11 at the same engine RPM.

@ 1:1 Top gear:
1 RPM at engine with a 4.11 = 1 / 4.11 RPM at wheels
1 RPM at engine with a 3.90 = 1 / 3.90 RPM at wheels

Rear wheels spin 1.0538 times faster at same engine RPM with 3.90 than with 4.11.
(4.11 / 3.90 = 1.0538)

At same engine RPM -
> 50mph with 4.11 = 52.7mph with 3.90 = (50mph X 1.0538)
> 60mph with 4.11 = 63.2mph with 3.90 = (60mph X 1.0538)

Replacing the rear end is your call.

A previous owner replaced the 3.90 in my '54 3104 with a 1950 4.11. I don't feel that I would gain enough to justify changing back to a 3.90 other knowing that I have the correct rear end. My ol' truck is no speed demon, so it's a moot point.

- Lonnie

- Lonnie
My '54 3104
Photos that I have shared on Stovebolt via PhotoBucket are no longer available. Please contact me if you want a photo from an old post.
lonniecook [at] aol [dot] com. I sold my '54 3104 12/12/2017, but I still visit Stovebolt.

OLD STUFF ... houses, furniture, cars, wine ... I love it all