It being a dually, wouldn't that make it a C30? Then again I am unfamiliar with the different aftermarket cab options that were done on these old trucks, and what drive train may have been used before the conversion was done. The extended cabs definitely have a look that doesn't agree with my eye, not these older 2wd versions anyhow. I wanted to buy a '65 4x4 suburban back in 1993 but they wouldn't sell it. I was in that town in 2015 for a job interview and it is still sitting there rotting away. Hopefully someone will scoop up that blue one before it goes to the crusher.
You definitely have a resto-mod going on there. I had considered modifying an original instrument cluster with modern gauges, but I now have three different clusters, so I have spare gauges. What rpm's do you turn going down the road? With the overdrive it's probably in the 2,100 range, depending on tire diameter.
