70 k/20 14 bolt swap questions and concerns - The 1947 - Present Chevrolet & GMC Truck Message Board Network

collin70k/20 · 01-03-2018, 08:11 PM

Im sure this question was asked plenty of times. But i have a 1970 k20 chevy pickup with eaton ho52. Well today is decided to take a crap on me. so the 14 bolt dually rear i have is going in this weekend. (pretty sure it has 11.5 ringear). Any how i know you have to cut the spring perches and shock mounts. thats no problem. My one concern is will the back driveshaft on the eaton work on the 14 bolt? Any other questions, pointers, or advice is greatly appreciated thanks Collin.

**Stocker** · 01-03-2018, 08:55 PM

Just curious, what went south in the Eaton?

collin70k/20 · 01-03-2018, 08:59 PM

Quote:

Originally Posted by Stocker

Just curious, what went south in the Eaton?

Axle broke.

sweetk30 · 01-03-2018, 10:42 PM

i have heard eaton rears can swap the axles and spider gears with 14ff axles .

and 14ff were 10.5 ring gear . latter 11.5 were aam axles if i recall correctly from 00ish up trucks .

**BlueBullet** · 01-03-2018, 11:02 PM

When I put in my 14 bolt in my 72 K20 I used the same drive shaft. My suggestion when you weld on the perchs have the axle on the truck, set the pinion angle, tac weld, then remove and weld up. I didn't have a big enough welder in my shop, so I went to our main shop and welded them on. I went off the angle of the original perchs, not a good idea. I think my angle ended up being off because the springs are different lengths on earlier models. Don't quote me on that but that is all I could come up with. Luckily I was able to shim it 6 degrees to get the proper angle. I could have avoided a $50 bill.

**jeffahart** · 01-04-2018, 01:18 PM

On my swap from HO52 to SRW corp14 I came up about 1/2" shorter yoke to yoke using zero rates on 1" setback. I made no drive shaft modifications. And definitely, dial in the perches for the pinion angle if you have to weld perches. But just for info sake, a one ton SRW corp14 will bolt directly into the K20 with only shock tab relocation. If you have a line on one of those with the right gears its a quick job.

j

Short 3/4 · 01-04-2018, 10:28 PM

Good luck on your project. If you get a chance please check out my WTB ad, as you may be pulling off stuff I need
Thanks, Tom

collin70k/20 · 01-05-2018, 05:59 PM

ok thanks everyone for the advice. it is going to be this weekends project.

01-03-2018, 08:11 PM	#1
collin70k/20 Registered User Join Date: Feb 2015 Location: Schaefferstown, PA Posts: 202	70 k/20 14 bolt swap questions and concerns Im sure this question was asked plenty of times. But i have a 1970 k20 chevy pickup with eaton ho52. Well today is decided to take a crap on me. so the 14 bolt dually rear i have is going in this weekend. (pretty sure it has 11.5 ringear). Any how i know you have to cut the spring perches and shock mounts. thats no problem. My one concern is will the back driveshaft on the eaton work on the 14 bolt? Any other questions, pointers, or advice is greatly appreciated thanks Collin. __________________ 1970 Chevy K20 pulling truck 406 small block 1967 Chevy K20 daily/street truck My daily 1970 k20 - http://67-72chevytrucks.com/vboard/s...=1#post7568564

01-03-2018, 08:55 PM	#2
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,728	Re: 70 k/20 14 bolt swap questions and concerns Just curious, what went south in the Eaton? __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

01-03-2018, 10:42 PM	#4
sweetk30 Registered User Join Date: May 2012 Location: horseheads,ny rust belt Posts: 2,794	Re: 70 k/20 14 bolt swap questions and concerns i have heard eaton rears can swap the axles and spider gears with 14ff axles . and 14ff were 10.5 ring gear . latter 11.5 were aam axles if i recall correctly from 00ish up trucks . __________________ 77-k30lb BIG truck build . 87-k30lb budget beater build . 85-k30lb the plow machine build . 85-c10sb summer fun toy . ----------------------------- HOLLEY SNIPER efi = worst case of p.i.t.a i ever had . EDELBROCK pro flo 4 = best deal going so far . love my setup works great.

01-03-2018, 11:02 PM	#5
BlueBullet Senior Member Join Date: Apr 2013 Location: Danvers Minnesota Posts: 967	Re: 70 k/20 14 bolt swap questions and concerns When I put in my 14 bolt in my 72 K20 I used the same drive shaft. My suggestion when you weld on the perchs have the axle on the truck, set the pinion angle, tac weld, then remove and weld up. I didn't have a big enough welder in my shop, so I went to our main shop and welded them on. I went off the angle of the original perchs, not a good idea. I think my angle ended up being off because the springs are different lengths on earlier models. Don't quote me on that but that is all I could come up with. Luckily I was able to shim it 6 degrees to get the proper angle. I could have avoided a $50 bill. __________________ 1972 K10 SWB wife's driver 1967 Pontiac GTO Big Bird - 1972 Longhorn K30 http://67-72chevytrucks.com/vboard/s...d.php?t=753294

01-04-2018, 01:18 PM	#6
jeffahart Senior Member Join Date: May 2012 Location: Scottsdale, AZ Posts: 1,907	Re: 70 k/20 14 bolt swap questions and concerns On my swap from HO52 to SRW corp14 I came up about 1/2" shorter yoke to yoke using zero rates on 1" setback. I made no drive shaft modifications. And definitely, dial in the perches for the pinion angle if you have to weld perches. But just for info sake, a one ton SRW corp14 will bolt directly into the K20 with only shock tab relocation. If you have a line on one of those with the right gears its a quick job. j __________________ White K20

01-04-2018, 10:28 PM	#7
Short 3/4 Registered User Join Date: Jan 2017 Location: Los Osos Ca Posts: 560	Re: 70 k/20 14 bolt swap questions and concerns Good luck on your project. If you get a chance please check out my WTB ad, as you may be pulling off stuff I need Thanks, Tom __________________ 65 short stepside K10 292-SM420-T221 8 lug closed D44 front NoSpin HO72 4.10 rear

01-05-2018, 05:59 PM	#8
collin70k/20 Registered User Join Date: Feb 2015 Location: Schaefferstown, PA Posts: 202	Re: 70 k/20 14 bolt swap questions and concerns ok thanks everyone for the advice. it is going to be this weekends project. __________________ 1970 Chevy K20 pulling truck 406 small block 1967 Chevy K20 daily/street truck My daily 1970 k20 - http://67-72chevytrucks.com/vboard/s...=1#post7568564



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