if not call Smith Brothers. They can make any push rod.

Just spitballin here. I used to make my own pushrods, when TRW had their engine parts catalog with size charts in the back. I would look up a 3/8 pushrod that was longer then what I needed, with the correct ends. Then removed the cup end (just pushed in) cut the tubing to the length I needed with a tubing cutter (or lathe). Take a drill bit and bore the open end slightly to the correct size, then push in the cup end. easy peasey. Mopar performance used to sell a cut to fit push rod kit for the V-8's that would also fit the slant six. I wonder if a company like Smith Bros. would sell a kit similar (tube with ball end, and loose cup end) to that if you weren't sure exactly what you needed.