Another Differential Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**PbFut** · 01-19-2025, 02:20 PM

I have little experience with solid rear ends. All the rear end experience I have is IRS. So nothing with axil hubs. My 72 as best I can figure is a peg leg 3.50. But I am not sure of that ratio. It does not have a round case so that tells me Dana. My searches come up with bits and pieces, but I am not finding a really good definative source for a 72 setup. A new Blue Print 400 is on its way. Tranny in for rebuild. I figure I may as well complete the Trio and swap the pegleg for a posi. With the horse power of the engine, that 3.08 gear set in the for sale section is tempting. Input and if you know of a good link for set of steps to disassemble it would be appreciated. Thanks all.

**Cali72K20** · 01-19-2025, 02:52 PM

It should have a Dana 60 with 3:54 or 4:10 gears.

https://www.scribd.com/document/3527...-X510-8DSD-pdf

Starting on Page 139 is the Dana 60 breakdown.

Keith Seymore · 01-19-2025, 02:52 PM

Generic info packet from the GM Heritage Center:

https://www.gm.com/content/dam/compa...olet-Truck.pdf

This will give original axle info and ratio availability (assuming your gear has never been changed).

I like a 3.40 or 3.42 ratio as a nice compromise between off the line performance and highway use with a non overdrive transmission. 3.73 for use with an overdrive trans.

K

**PbFut** · 01-19-2025, 07:42 PM

Thank you both.
Looks like I have my reading assignment for the week.

01-19-2025, 02:20 PM	#1
PbFut Senior Member Join Date: Feb 2022 Location: Ca Posts: 1,024	Another Differential Question I have little experience with solid rear ends. All the rear end experience I have is IRS. So nothing with axil hubs. My 72 as best I can figure is a peg leg 3.50. But I am not sure of that ratio. It does not have a round case so that tells me Dana. My searches come up with bits and pieces, but I am not finding a really good definative source for a 72 setup. A new Blue Print 400 is on its way. Tranny in for rebuild. I figure I may as well complete the Trio and swap the pegleg for a posi. With the horse power of the engine, that 3.08 gear set in the for sale section is tempting. Input and if you know of a good link for set of steps to disassemble it would be appreciated. Thanks all.

01-19-2025, 02:52 PM	#2
Cali72K20 Senior Member Join Date: Aug 2013 Location: CA \ OK Posts: 2,766	Re: Another Differential Question It should have a Dana 60 with 3:54 or 4:10 gears. https://www.scribd.com/document/3527...-X510-8DSD-pdf Starting on Page 139 is the Dana 60 breakdown. Last edited by Cali72K20; 01-19-2025 at 02:57 PM. Reason: wrong number

01-19-2025, 02:52 PM	#3
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,490	Re: Another Differential Question Generic info packet from the GM Heritage Center: https://www.gm.com/content/dam/compa...olet-Truck.pdf This will give original axle info and ratio availability (assuming your gear has never been changed). I like a 3.40 or 3.42 ratio as a nice compromise between off the line performance and highway use with a non overdrive transmission. 3.73 for use with an overdrive trans. K __________________ Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/

01-19-2025, 07:42 PM	#4
PbFut Senior Member Join Date: Feb 2022 Location: Ca Posts: 1,024	Re: Another Differential Question Thank you both. Looks like I have my reading assignment for the week.



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