47-55.1 51 Chevy 3600 Differential/Center Section Options - The 1947 - Present Chevrolet & GMC Truck Message Board Network

agraff · 02-21-2026, 04:05 PM

I have a 1951 Chevrolet 3600 with an Eaton HO52 rearend (8 lug axles, 4.56 gears). It has an open driveshaft (no torque tube). I would like to keep as much original equipment as possible so I’m looking for options for a direct differential/center section swap that can get me 4.11 gears or lower to help with cruising speed.

I have heard that the 67-72 C/K 20 models should be a direct swap, anyone know of other options to get me a little better gear ratio?

**mr48chev** · 02-21-2026, 04:19 PM

Here is the exact info you are looking for, Finding a 68/72 coil spring C20 with 350 and automatic in a wrecking yard with a good third member might be a bit of a challenge. In truth the hard part will be finding a good donor.

https://www.stovebolt.com/techtips/a...Ton%20Upgrade/

This is good info that I am saving to my favorites as I see people ask the same question all the time. I'd be looking more at 69/72 potential donors though. GMC is leaf spring and often as not has a Dana 60 as my 71 GMC does.

02-21-2026, 04:05 PM	#1
agraff Registered User Join Date: Jan 2024 Location: South Dakota Posts: 1	51 Chevy 3600 Differential/Center Section Options I have a 1951 Chevrolet 3600 with an Eaton HO52 rearend (8 lug axles, 4.56 gears). It has an open driveshaft (no torque tube). I would like to keep as much original equipment as possible so I’m looking for options for a direct differential/center section swap that can get me 4.11 gears or lower to help with cruising speed. I have heard that the 67-72 C/K 20 models should be a direct swap, anyone know of other options to get me a little better gear ratio? Last edited by agraff; 02-21-2026 at 05:03 PM.

02-21-2026, 04:19 PM	#2
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 16,391	Re: 51 Chevy 3600 Differential/Center Section Options Here is the exact info you are looking for, Finding a 68/72 coil spring C20 with 350 and automatic in a wrecking yard with a good third member might be a bit of a challenge. In truth the hard part will be finding a good donor. https://www.stovebolt.com/techtips/a...Ton%20Upgrade/ This is good info that I am saving to my favorites as I see people ask the same question all the time. I'd be looking more at 69/72 potential donors though. GMC is leaf spring and often as not has a Dana 60 as my 71 GMC does. __________________ Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around.



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