I am not to sure just what the advantage would be to swap out a complete chassis, in lieu of just up-grading what the vehicle has.
My brother picked up a '63 C10 fleetside 6' bed pickup that had been rolled. The previous owner had done a lot of work to the truck, so my brother thought it would be an easy fix. Wrong, turned out the body had extensive rust-out that had been Bondo'd over. I had a very nice '64 cab that we put on the truck solving the body issue. We took the truck to a good body repair shop that had a frame rack, adjustments were made to the frame to correct any issues the roll-over might have caused.
A complete '78 C10 front assembly and a 343 rear axle assembly was obtained. Removing 16 bolts from the front assembly, replacing it with the '78 assembly solved that problem, a perfect fit that only requires the elongation of two bolt holes. We retained the original rear coil spring suspension, installing the '78 unit. Following the assembly of the running gear under the truck we took the truck to an alignment shop to have the alignment check.
We used the VIN number for the cab to make the truck legal. It is all restored now, painted GM red with AC, PB, PS, the truck has won several awards at various car shows in the inter-mountain west.
A different approach was used with my '64 C10 RR trk.. The extended cab trucks are very rare so we decided to really up-grade the truck.
I obtained a '98 C10 Z71 extended cab that had been stolen and vandalized. We discarded the body from the truck, keeping the firewall portion of the cowl and half of the floor pan.
We harvested the body mounts from the original '64 chassis which were positioned onto the '98 chassis. We then removed the firewall and floor pan up to the front of the drivers seat, replacing same with the '98 unit. The '64 rear coil spring assembly was fitted to the '98 chassis.
The truck now has it's original 5.7 V8 w/4L60 trans and 343 rear axle, PB, PS, PW, & AC. The truck is a dream to drive. Wm.
