62 c20 Rear end swap

[R_Kling]

Anyone here swapped a big heavy 12 bolt out for a 72 c10?
Bad Idea? I've got a big block and a 700R4.
I,m really just trying to match 5lug bolt pattern.
But wondering if I'm downsizing too much.


Almost done with front end swapped in a 73 whole crossmember.
Rear end is next.

[Captainfab]

There's absolutely nothing wrong with a truck 12 bolt. In stock form they will hold up to quite a bit. Of course this is relative to just how much torque your big block produces the tires you bolt on each end of the differential. If that 700R4 isn't built right, it won't last long behind a high torque big block. Be aware that you will have to move the trailing arm mounts to bolt up anything other than a '60-'62 differential. I do make those if you need a pair.

[R_Kling]

Feel I must clarify.
SO I have a 62 c20. I'm contemplating pulling the 3/4 ton rear end and replacing it with one from a 72 1/2 ton. Basically rendering my truck a c10 w 5 lugs.
It seems like the only installation trickery will be trailing arm brackets for new angle and position on the axle. Wondering if anyone has done this or if this is a bad idea for any reason.

[Fatherof3]

Very interested in this too as I have 65 C20 with Eaton HO52 I want to swap for a rearend that has better freeway gears. Drive line length and brake size are concerns. Willing to stay 8 lug or convert five lug

[Captainfab]

I have done a similar swap many years ago and I see no reason not to if you are wanting to change your truck to a 1/2 ton with the 5 x 5" wheel stud pattern.

[R_Kling]

HEy there. You mentioned that you have trailing arm brackets that I will need.
Im swapping out my 62 3/4 ton rear end for a 72 1/2 ton. Seems like it's only the trailing arm relocation that I,lll have to deal with. Does that sound right? Since the72 perches are located farther in away from the brake drums than the 62. And I,m only going to lower it 2 inches so won't need to worry about the anti squat stuff. But it does seem like the pan hard bar is situated differently as well. Have you done this swap?

Frankenstein 62 long bed. Will have a 73 front end, and a 72 rear end hopefully. Then should drive & stop a whole lot smoother.
Big block is not beefed up just stock 454
But my 700r4 has been modified to handle it.

[R_Kling]

Thanks so much. I'm curious though. DO you think it's best to have the location of trailing arm where they went on the 62 using the new perches? Or try to move them in a couple inches away from brake drum where the perches are on the 72 rear end already. I'm assuming that was a geometric upgrade.
But to do that I'd need new brackets for where they mount to crossmember.
They would have a narrower angle on them.