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Old 06-05-2015, 03:02 AM   #1
billdozer
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Rear end gearing question

I've got a '49 3100 with a 4 speed on the floor with torque tube and stock rear end mated to a strong-running 261. I don't pull many houses down, so the granny gear is essentially useless, and I top out at about 45mph. It'll go faster, but it's comfortable under 50 for sure. I'd like to get it to cruise around 60-65 in 4th. I know about the T-5 trans conversion, but would like to keep it sort of period-correct (despite the disc brakes up front) and just swap the rear end gears to something taller to get better top speed. Tires are about 28" tall. I don't pull anything with it, but do haul a motorcycle and other stuff in the bed so I don't want it to be a slug. I mostly drive it on the street but wouldn't mind hopping on the freeway once in a while. 45MPH here in So Cal is suicide, but I think I could survive around 60-65MPH.

Anyone done this? Care to share how it changed driveability? Anything to worry about with this, or any reason not to?

(I searched first and didn't really find what I was looking for. Thanks for any input!)
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Old 06-05-2015, 08:28 AM   #2
Katrina/10
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Re: Rear end gearing question

I think you'll have to swap the whole rear axle to get what you want.
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Old 06-05-2015, 08:41 AM   #3
xaircav
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Re: Rear end gearing question

Patrick's Car & Truck Parts in Casa Grande AZ makes 3.55 and 3.38 gears for the old style torque tube rear ends.
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Old 06-05-2015, 11:51 PM   #4
billdozer
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Re: Rear end gearing question

Thanks guys.
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Old 06-06-2015, 07:42 AM   #5
Old Crow
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Re: Rear end gearing question

We used the Patrick's kit to do the '54 truck we're building at the shop. Not finished yet, so no driveability review.
I'm also doing Newfisher's T-5 swap on my wife's '54 panel at home.
Between the 2, I'm actually going to have less money in the T-5 swap(including swapping out the rear end and having a driveshaft made)than the guy has in the re-gearing project.
Just a thought. Once the T-5 swap is done and the rear end swapped out, a future eng/trans swap is that much easier.
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