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Old 10-21-2005, 11:35 AM   #1
Hilandr451
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What's the difference in diferentials? or What ratio Horatio?

Hey fellas,
As usual, I'm sitting here contemplating rear-ends....for my truck that is. What I've got is a C20 with a "mutt 327" power plant that I'm building for a daily driver and a tow vehicle for my 26' vintage Airstream trailer. I'm thinking of running a 700r4 in front of a 'Gear Vendors' gear splitter at stock height with 16" rims & close to stock tires.

I have a really low geared differential in it now (60MPH @ 3-1/2 grand tops) and I was wondering what gear ratio would be ideal for what I want to do with the truck. I'll be doing a great deal of highway driving, but mountain passes & campground manouvering should be considered as well.

Economy, of course, is a big concern here and I would like to be able to cruise at 75 when I'm not hooked up to the trailer - at the same time, I don't want to loose all of my torque off the line. Anybody know about ratios? Any advice would be great.
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Old 10-22-2005, 01:16 PM   #2
special-K
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Re: What's the difference in diferentials? or What ratio Horatio?

With all that o/d you`d want to keep the rear ratio low,Joe.That`s what my book says,Hernandez.
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Old 10-23-2005, 02:04 AM   #3
Fred T
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Re: What's the difference in diferentials? or What ratio Horatio?

Something's not adding up here. Your ratio should be 4.57, stock for a C-20 with 4 speed. But to get that and the numbers you gave to work the tire size has to be 26". Far from stock. The 5.14 gears come up with your numbers using a 30" tire.

I would recommend the OD tranny, but now the second splitter.
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Old 10-23-2005, 10:31 AM   #4
64fleetside
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Re: What's the difference in diferentials? or What ratio Horatio?

I would run a pumpkin from 70-72 3/4 ton auto, most of these were 4.10, using a 700R4 would pull great & get decent mileage. I like the GV unit, just $2k is hard to swallow, there was good 700 in a wrecked 94 c1500 at U-pull-it for $300 yesterday. My 2 cents, Brian
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Old 10-25-2005, 03:04 AM   #5
rwgregory
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Re: What's the difference in diferentials? or What ratio Horatio?

If it were me, I would go with either a 3:73 or 4:10 rear gear and run tall 33"
rear tires. FYI: 33" tires w/ 4:10 rear gears = 2600 rpm with trans in high
gear (1 to 1 ratio).
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