HardyRestoration,
The best bet would be to go to your friendly muffler guy..he has all the answers. I don't think the '85 rigs had OBD1, so the system isn't "looking" at the converter (not sure on this). If Texas doesn't have yearly inspections or isn't California Smog Crazy, I don't know why another cat would be needed.
Leaving the converter intact is a smart move from an environmental standpoint, and if you are going with twice pipes, it wouldn't hurt to install another one. I think it would be a cost/environment decision. Each pipe would require a muffler, no question on this!
Stuart
