C4 Output Shaft - Slip Yoke - Drive Shaft - Pinion Yoke?
If the driveshaft guy doesn't know that stuff already, you might consider going somewhere else.
Or, just go to the junkyard and get your own slip yoke and pinion yoke.
That way you know they are right.
Then all he needs to know is the length.
Got mine done this way, it cost $180.00 with huge Spicer U-joints and a full balance job.