Frankenstien Help

[jwaldo880]

I'm working on a 68 GMC and have hit a road block with the frame and rear end.
The truck has front disc brakes / rear drums with a 5x5 wheel pattern, leaf springs in the rear. No VIN stamped on the driver side frame rail next to the motor and I am trying to avoid pulling the cab. Any other thoughts on how to identify what I might have frame wise. My next step is to get it up on a lift this weekend and take some pics and measurements.

The rear end has me puzzled even more. 10 bolt, 8.5 rear end but the axle stamp is BN3 G212 2 which according to the GM website would be a 3.08 in a 12 bolt. This obviously doesn't match unless I am reading the code wrong on the tube. Several other numbers on the pumpkin that look like casting numbers.

My brain is fried. Thanks in advance

[Blue GMC]

Honestly your frame may not be stamped as GMC i know did not stamp the 67 frames. If it was an early production 68 may not be stamped as well. Not hard to change over to a disc break set up off a donor truck which someone may have done in the past for safety.

[jwaldo880]

What about the leaf springs, thought they didn't change over to leafs until 70?

[57taskforce]

Gmc's seem to be more common with leaves in my expierence but coils or leaves could be had from the factory in any of the 67-72 Chevy/gmc trucks. They were both available all the way thru the production run.

[jwaldo880]

Thanks guys. Any thoughts on the rear end. I had suspected that a donor rear end might have been used but the numbers BN3 G212 telling me it is a 308 12 bolt really confuses me as it is a 10 bolt 8.5

[Daves70]

The rear is likely a mid 80's rear end out of a square body truck. The front end parts for the disk brakes could very well be off the same truck. Your frame may be original to the truck.

[Mike C]

How wide are the leaf springs? 67-72 2x4 trucks should be 2 1/4" wide. If they are 2 1/2" that opens up a whole 'nother can of worms.

[Steeveedee]

There are some real gurus in here that can tell you what you have in the way of a frame with a few pictures. What does the SPID look like? If you want to post a pic of the SPID, maybe leave the serial number off the top edge, for personal security reasons.

[jwaldo880]

Mike C the leafs at 2 1/4. Thats a huge help as I was questioning if I might have a car frame.

[jwaldo880]

Steevedee, unfortunately I am not a guru, just a shade tree tackling a project with my son....so what does SPID stand for?

[clay68c10]

The SPID is the option sheet stuck to the inside of the glovebox door. It lists all the options your truck came with. The SPID isn't always there, or may not be readable.
Mine is long gone after a repaint in 91.

I'd bet someone swapped in square body parts, that's a common and easy way to get rid of the front drum brakes. That swap also changes over to 5 lug from 6. Not a big deal, I'd say it's a bonus.

[jwaldo880]

Thanks Clay, the plate in the glove box is gone. I have found the vin for the cab and numbers off the motor and transmission, the frame and the rear-end are the two that have stumped me. My main concern is ordering parts as I don't know exactly what to get, so I'm guessing a little trial and error at the local auto parts store is in my future. I do like the 5 lug as it seems like I have better wheel options and the disc brakes on the front are a bonus, would be nice if I could convert the rear as well.