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Old 10-08-2014, 10:57 PM   #1
aotte1
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72 K10 SB 1/2 or 3/4 Axles?

Recent purchase of 1972, K10 short bed with 3/4 ton axles (Dana 44 front and 60 rear). Plan to keep the truck mostly stock. Question is to keep the axles or replace them with 1/2 ton units? Truck will have the easy life now. For the front just need to change from 8 lugs to 6 lugs?? What axle was in the rear- 12 bolt?

Thoughts keep or change to 1/2 ton?

Les
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Old 10-09-2014, 12:29 AM   #2
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Re: 72 K10 SB 1/2 or 3/4 Axles?

Unless one (or both) of those axles are bad and need to be replaced, I would just leave them. I kinda like the mechanical bits to be sturdier than they need to be.... And I think you have bigger brakes than on 1/2T axles, too.

Looks like a good straight truck with what, about a 4" lift? Could use taller tires hehe...
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Old 10-09-2014, 11:20 AM   #3
aotte1
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Re: 72 K10 SB 1/2 or 3/4 Axles?

Mike,

Not sure if lifted, does look high, just got the truck so not real knowledge on the truck. Could the springs be 3/4 ton and raise it up like it is or it could have lift springs??

Probably the wheels/tires for it may drive my decision some, on which axles to use.
Thinking of using stock GM steel wheels, 8 inches wide.

Les
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Old 10-09-2014, 02:33 PM   #4
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Re: 72 K10 SB 1/2 or 3/4 Axles?

Stock 3/4T springs are stiffer & heavier than 1/2T springs, but have little to no lift. I'm sure you have lift springs up front. Rear could be springs or blocks, easy to tell by looking. Blocks are cheaper so they get used a lot.
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Old 10-09-2014, 07:58 PM   #5
aotte1
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Re: 72 K10 SB 1/2 or 3/4 Axles?

Mike,
Checked, it does have blocks in the rear. Maybe 4" or a little less.

Know of any members who have stock 4x4 trucks, would like to see photos of stock trucks.. Sometimes think the photos in the sales brochure are touched up some.

Les
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Old 10-09-2014, 09:17 PM   #6
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Re: 72 K10 SB 1/2 or 3/4 Axles?

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Originally Posted by aotte1 View Post
Mike,
Checked, it does have blocks in the rear. Maybe 4" or a little less.

Know of any members who have stock 4x4 trucks, would like to see photos of stock trucks.. Sometimes think the photos in the sales brochure are touched up some.

Les
my '69 with stock suspension
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Old 10-09-2014, 09:44 PM   #7
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Re: 72 K10 SB 1/2 or 3/4 Axles?

KyFarm

Thanks, I am interested in what wheels you are using ( width and BS) and tires.

Les
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Old 10-10-2014, 07:24 AM   #8
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Re: 72 K10 SB 1/2 or 3/4 Axles?

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KyFarm

Thanks, I am interested in what wheels you are using ( width and BS) and tires.

Les
The wheels are stock rallys - 8" wide

The tires are Falken WildPeak AT, 32 x 11.5 x 15
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Old 10-10-2014, 09:08 AM   #9
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Re: 72 K10 SB 1/2 or 3/4 Axles?

Mike,

Please provide any references here, for photos and information on your truck as to how it sits for height, Stock vs lift, wheel and tire size. Thanks.

Beginning to learn more about new to me 72, rear is Dana 60, maybe a 71', from casting number, still looking for date code. Front, looking for Dana 44 date code. Have not found either ratio code stamped on axle tubes yet. For the Dana 60 rear, if 71' and standard, it may be 4:11. Still thinking about what ratio I would like, it has a four speed trans.

Les
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Old 10-10-2014, 09:22 AM   #10
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Re: 72 K10 SB 1/2 or 3/4 Axles?

Could always pull the diff cover and look and see what the ratio is. The teeth count is stamped into the ring gear. Doing this is the only real way to know what you have. Can also tell real quick if there is a posi unit in there. My 72 K20 has the Eaton rear. As a basic rule of thumb the 3/4 drivetrain is 4.57 gears. 4.10s pretty much only came with the 350 4spd combination. Might be an exception for the Dana axle or it could of been regeared at some point. Gears are readily available for both the Dana 44 and 60. I would keep the heavy drivetrain. I broke more 12bolt rears than I want to think about. Truck 12 bolts are no stronger than a 10 bolt. They are a different animal than car 12 bolts.
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Old 10-10-2014, 09:43 AM   #11
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Re: 72 K10 SB 1/2 or 3/4 Axles?

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This is my LWB with 4" lift springs all around and 15x8 steel rally wheels and BFG 33/12.50's. I toyed with the idea of 3/4 ton axles, but the halls are plenty stout and good enough for the girls I date.

Jeff
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Old 10-10-2014, 06:22 PM   #12
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Re: 72 K10 SB 1/2 or 3/4 Axles?

I'd be happy to trade my 72 K10 diffs, etc. for the K20 setup the OP has...
Bring it on down to DFW and we'll get started.
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Old 10-11-2014, 12:08 PM   #13
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Re: 72 K10 SB 1/2 or 3/4 Axles?

Thanks for the offer, not ready to make decision. Leaning toward keeping them at this time.

Les
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Old 10-11-2014, 09:27 PM   #14
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Re: 72 K10 SB 1/2 or 3/4 Axles?

before you decide to pull the heavier axles out, decide the tire height you want to run. That will decide the gear ratio best to keep the truck from being a slug on the highway. Its costly to regear. 3/4 ton and 1 ton axles are a cheaper option.
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Old 10-11-2014, 09:49 PM   #15
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Re: 72 K10 SB 1/2 or 3/4 Axles?

Mine has a four inch lift with stock 3/4 ton springs. Lift was done with new brackets and shackles. Very stiff ride for a short wheel base truck
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Old 10-14-2014, 10:15 PM   #16
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Re: 72 K10 SB 1/2 or 3/4 Axles?

Thanks for all the help, will check what ratio they are, along with condition.

Les
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Old 10-15-2014, 12:29 PM   #17
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Re: 72 K10 SB 1/2 or 3/4 Axles?

Here is a stock suspension with 31x10.50-15's...
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