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