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11-18-2020, 11:28 AM
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#1 |
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Senior Member
 
Join Date: Jun 2011
Location: burlington,iowa
Posts: 439
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68 gmc c30
looking to replace/upgrade stock rear differential on my 68 c30 dually, Will be running low HP big block with turbo 400. What do you suggest.
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Tom in Iowa 68 L88 C10 68 4x4 C10 soon |
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11-18-2020, 11:54 AM
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#2 |
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Registered User
Join Date: Jan 2011
Location: Delaware and Long Island, New York
Posts: 3,455
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Re: 68 gmc c30
14 bolt 4:10
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11-18-2020, 11:58 AM
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#3 |
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Senior Member
Join Date: Nov 2018
Location: Waterford California
Posts: 2,588
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Re: 68 gmc c30
73-87 14 bolt cab n chassis will bolt right in. Just have to cut off and relocate shock mounts. 4.10 ratio is probably most common out there. Too bad you're in Iowa as I have complete one drum to drum (4.10)I no longer need.
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11-18-2020, 06:51 PM
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#4 |
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Special Order
  
Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,852
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Re: 68 gmc c30
What you have is a '68 GMC C3500. C/30s are Chevrolets. The HO52 can handle all that a 14-bolt can. But if you have some other reason to replace, then a 14-bolt is the simple solution. You can get them in 3.73 or even 3.42:1.
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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11-18-2020, 07:29 PM
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#5 |
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Senior Member
Join Date: Nov 2018
Location: Waterford California
Posts: 2,588
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Re: 68 gmc c30
What Tim says is true (I think he meant H072) but the draw back to the original H072 is parts, ring and pinions are non existent. Rear drums are hard to get also but they can be upgraded to the 14 bolt backing plates and drums.
The 14 Bolt 10.5 Corporate Rear Differential was produce from 1973 until 2013 Parts are readily available and abundant. I swapped mine out because my pinion seal was leaking but I was also thinking of the future when mileage/wear and tear took it's toll plus I wanted to upgrade my front brakes to disc, so I purchased the complete front cradle and rear differential from a 1986 Cab n Chassis 3500. Here's what I did:http://67-72chevytrucks.com/vboard/s...d.php?t=803011 |
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11-19-2020, 06:26 AM
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#6 |
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Special Order
Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,852
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Re: 68 gmc c30
Yep, HO72... Thanks. The only correction I have to make is those parts aren't available "new". But there are plenty of good ring & pinions available, as well as other hard parts, used sitting inside the HO rears that people pulled out. I have a stash of rears, so I should be good. But I also have some 14-bolts, you know, just in case
 . You can also run an HO rear using 14-bolt guts if you really want to keep that original rear "appearance"
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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11-19-2020, 11:45 AM
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#7 |
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Senior Member
Join Date: Mar 2000
Location: Saskatoon,SK,Canada
Posts: 2,476
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Re: 68 gmc c30
And Actually a Single wheel 14 bolt will also swap into a dually. The PO of my C30 dropped one into it. It still has the single wheel rear hubs on it too. Not sure all he did or didn't to make it work but clearly the width was right.
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