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Old 12-29-2022, 12:15 AM   #1
'64C20
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64 C20 with 71/72 12 Bolt Swap

Has anyone dropped a 12 bolt into the back of their 64-66 C20?

Along with this, has anyone lowered theirs at all?

I have a '64 that I've dropped a 72 12 bolt into while also using a 3/5 spring lowering kit. The issue I am running into is the track bar. The current one is too long and I would need some sort of dog leg to connect to the factory 12 bolt stud.

I contacted CPP asking if one of their drop bar kits would work with the factory C20 trailing arm factory reinforcement plates. To my surprise, they said yes...to my surprise the trailing arm mount does not work with the plates. Before I start grinding rivets and removing the plates, has anyone come up with an off-the-shelf solution to this?
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Old 12-31-2022, 07:55 AM   #2
The Rocknrod
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Re: 64 C20 with 71/72 12 Bolt Swap

The 72 trac bar mount is cast into the 12 bolt center section.
You coud buy theyre (CCP) custom trac bar with a bend in it for custom rear end covers - https://www.google.com/imgres?imgurl...caiMaViNxPNgvM
Or a straight unit for stock rear end covers - https://www.performanceonline.com/19...-bar-trac-bar/
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Old 12-31-2022, 01:23 PM   #3
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Re: 64 C20 with 71/72 12 Bolt Swap

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Originally Posted by The Rocknrod View Post
Or a straight unit for stock rear end covers - https://www.performanceonline.com/19...-bar-trac-bar/
From experience this won’t work as is. The frame mount for the panhard is at the wrong angle on 63-64s for putting the 65-72 rears into. I put a bend into mine which I don’t know is the right way, also makes it more difficult to adjust. I couldn’t open the link to the other you posted but that might be a better option.
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Old 01-01-2023, 02:47 AM   #4
cwcarpenter98
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Re: 64 C20 with 71/72 12 Bolt Swap

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Originally Posted by Mack B View Post
From experience this won’t work as is. The frame mount for the panhard is at the wrong angle on 63-64s for putting the 65-72 rears into. I put a bend into mine which I don’t know is the right way, also makes it more difficult to adjust. I couldn’t open the link to the other you posted but that might be a better option.
It can work, but definitely is tight. I didn't realize it at the time I did mine (65-70 axle in my 63) but got the track bar on and torqued. Haven't noticed any issues from it over the past about 6 years. I do have a 65-72 frame side bracket to replace the 63-64 bracket next time I take the bed off
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1963 C10 - Frankentruck 283, 3 speed with overdrive
Overdrive wiring here
1963-ish truck bed trailer - Half-Wit

1981 C10 - Penny 305, th350

1995 Dodge Dakota Sport

"I'll put it simple: if you're going hard enough left, you'll find yourself turning right." - Doc Hudson
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Old 01-01-2023, 06:47 AM   #5
Mack B
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Re: 64 C20 with 71/72 12 Bolt Swap

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Originally Posted by cwcarpenter98 View Post
It can work, but definitely is tight. I didn't realize it at the time I did mine (65-70 axle in my 63) but got the track bar on and torqued. Haven't noticed any issues from it over the past about 6 years. I do have a 65-72 frame side bracket to replace the 63-64 bracket next time I take the bed off
You using the adjustable aftermarket rod? Reason i ask the bushings are smaller and harder than stock. Also i definitely knew I was doing wrong by the effort it took to get it installed.

I experienced bushing failure a few years after first install. I can’t say for certain this was the cause but feel it likely was.
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Old 01-01-2023, 07:47 PM   #6
cwcarpenter98
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Re: 64 C20 with 71/72 12 Bolt Swap

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Originally Posted by Mack B View Post
You using the adjustable aftermarket rod? Reason i ask the bushings are smaller and harder than stock. Also i definitely knew I was doing wrong by the effort it took to get it installed.

I experienced bushing failure a few years after first install. I can’t say for certain this was the cause but feel it likely was.
Yes, I'm using an aftermarket adjustable one. I haven't noticed any issues with bushing failure yet, but then again, I also haven't looked at it in a couple years
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1963 C10 - Frankentruck 283, 3 speed with overdrive
Overdrive wiring here
1963-ish truck bed trailer - Half-Wit

1981 C10 - Penny 305, th350

1995 Dodge Dakota Sport

"I'll put it simple: if you're going hard enough left, you'll find yourself turning right." - Doc Hudson
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Old 01-02-2023, 04:52 PM   #7
'64C20
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Re: 64 C20 with 71/72 12 Bolt Swap

I got this to work. I used the deluxe bent trac bar. I cut the plates off the C20's trailing arms and it slid right on.
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