66 12 bolt in a 68 truck

[68C101775]

Good morning all,

I’ve got a lead on a built truck 12 bolt from a 66 that I’d like to purchase to throw under my 68 long bed.

Can anyone confirm for me that it’ll bolt right up? The measurements backing plate to backing plate look very close.

[SCOTI]

Originally Posted by 68C101775

Good morning all,

I’ve got a lead on a built truck 12 bolt from a 66 that I’d like to purchase to throw under my 68 long bed.

Can anyone confirm for me that it’ll bolt right up? The measurements backing plate to backing plate look very close.

Housing widths should be the same if both housings are pre-70. Things break & can be changed out over the years so it's always best to verify housing width for each.

The only other watch-out would be verifying where the Panhard bar mount is located on the 66 housing. The 1st gen C10's utilized different Panhard bar anchor locations on the rear end (and a slightly different frame bracket as well) vs 67-72's.

All 67-72's had the housing PHB mount/stud @ the differential.
Early 1st gen C10's had the housing PHB mount on the axle tube & then @ the differential. Not sure of the date range when the change happened but I believe it was sometime late 65 into 66 so it's something to identify & plan for. Of course if going to an aftermarket (long style) PHB, the differences are a wash.

[68C101775]

Thanks for that info that’s great. It does look like the PHB mount is on the tube. Do you know if I’ll beable to bolt up to the 68 frame mount with an aftermarket PHB?

[SCOTI]

Originally Posted by 68C101775

Thanks for that info that’s great. It does look like the PHB mount is on the tube. Do you know if I’ll beable to bolt up to the 68 frame mount with an aftermarket PHB?

The aftermarket 'long' Panhard bars attach to the housing @ the pass side u-bolt area so most (all?) of them have proprietary brackets for each end (housing + frame). The 'long' bars are better because they reduce the amount of sideways movement as the truck's suspension cycles between compression & extension.

[68C101775]

Cool I’ll look into that. Thanks a ton for the info!

['68OrangeSunshine]

I'm running a 1962 12-Bolt core, rebuilt, on my '68 C/10. It's the same thing, just older.
I had a '69 12-Bolt that had an Eaton Posi, but that got bent way outta shape when I got T-Boned in April 2022. After a 500 mile break-in, and a Prop Shaft rebuild, it runs good. I had the Eaton Posi rebuilt, too, but have not had it installed yet.