3/4ton Rear End Swap Questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Don Quixote · 02-01-2013, 08:24 PM

My '72 C25 has a 14-bolt sf rear (9.5") with 3.73s and I am looking into swapping in a 14-bolt ff rear (10.5"), maybe with 4.10s as I am also contemplating a ranger box as well. I have found a duelly in a '91(?) but I don't know how much trouble I will have with the swap or should I keep looking for a single. I tow a lot with this truck but I want to keep it a single. Any advise would be helpful.

Mike C · 02-02-2013, 11:14 AM

Look for the single wheel. Unless you need the extra gear, I'd stay with what you have persoanlly. The 9.5" semi-float is a pretty stout axle and at least up to par with the rest of a 67-72 truck in terms of load carrying.

But if you are going to do it, definitely get the single wheel, and look for the one with the bigger brakes.

Don Quixote · 02-02-2013, 02:00 PM

I have to admit that that rear pulls my 15000 lb trailer cross country like a champ but I worry about the bearing supporting the weight that wouldn't be an issue with a full floater. I am getting a bit of a coast vibration but nothing major yet. Thanks for the input. I didn't realize that the duelly rear was that different..
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Mike C · 02-02-2013, 08:17 PM

A dual wheel 14 bolt is from a cab and chassis truck which is a little different than the true dually axle which will be a Dana 70 HD. The C&C 14 is not as wide as the dually axle, but the 70 is way too wide for a single wheel use.

I have a semi-float 14 in my Jimmy and it is leaps and bounds ahead of the 12 bolt it replaced.

02-01-2013, 08:24 PM	#1
Don Quixote Registered User Join Date: May 2008 Location: Woodlawn, TN Posts: 275	3/4ton Rear End Swap Questions My '72 C25 has a 14-bolt sf rear (9.5") with 3.73s and I am looking into swapping in a 14-bolt ff rear (10.5"), maybe with 4.10s as I am also contemplating a ranger box as well. I have found a duelly in a '91(?) but I don't know how much trouble I will have with the swap or should I keep looking for a single. I tow a lot with this truck but I want to keep it a single. Any advise would be helpful. __________________ Rocinante: 1972 GMC C25, 292, SM465, 14 bolt, power nothing, 440k and still handles my PCS moves Jorge: Kia Roller-skate with lots of buttons for the wife Wovoka: 2017 Indian Chief Vintage, better on gas but not much So far, this is the oldest I've ever been.

02-02-2013, 11:14 AM	#2
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,727	Re: 3/4ton Rear End Swap Questions Look for the single wheel. Unless you need the extra gear, I'd stay with what you have persoanlly. The 9.5" semi-float is a pretty stout axle and at least up to par with the rest of a 67-72 truck in terms of load carrying. But if you are going to do it, definitely get the single wheel, and look for the one with the bigger brakes. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

02-02-2013, 02:00 PM	#3
Don Quixote Registered User Join Date: May 2008 Location: Woodlawn, TN Posts: 275	Re: 3/4ton Rear End Swap Questions I have to admit that that rear pulls my 15000 lb trailer cross country like a champ but I worry about the bearing supporting the weight that wouldn't be an issue with a full floater. I am getting a bit of a coast vibration but nothing major yet. Thanks for the input. I didn't realize that the duelly rear was that different.. Posted via Mobile Device __________________ Rocinante: 1972 GMC C25, 292, SM465, 14 bolt, power nothing, 440k and still handles my PCS moves Jorge: Kia Roller-skate with lots of buttons for the wife Wovoka: 2017 Indian Chief Vintage, better on gas but not much So far, this is the oldest I've ever been.

02-02-2013, 08:17 PM	#4
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,727	Re: 3/4ton Rear End Swap Questions A dual wheel 14 bolt is from a cab and chassis truck which is a little different than the true dually axle which will be a Dana 70 HD. The C&C 14 is not as wide as the dually axle, but the 70 is way too wide for a single wheel use. I have a semi-float 14 in my Jimmy and it is leaps and bounds ahead of the 12 bolt it replaced. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax



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