I was putting the last couple of firewall gaskets on the heater box for my a/c equipped 70 Challenger and realized that the drain tube that runs through the firewall had been broken off at some point in the past. It turns out that 3/4" CPVC pipe has the same inside diameter as the original drain, so I sanded off what was left of the old drain, widened the hole in the box a bit with a Dremel, and then used JB Weld to secure the new drain in place. If one of you can tell me how long the drain is supposed to be, I'd be grateful. I want to cut the drain to length and paint if before installing the box in the car. Based on the pictures I could find on the internet, something around 2" looks right but it's hard to tell for sure.
I'm not building a "numbers matching" car, so I'm mostly interested in making sure this drain is functional. Thanks.