42RH / A-500 in a Duster with pictures.

DartJack,

Check out the thread with the title "Will GM 200R4 work with factory floor shifter" (it's about 15-20 on the front page of Drivetrain and Transmission). I own a '69 barracuda with factory auto console and am in the process of mocking up the 200R4 to fit in my car. I don't think your using 200R4 but you're going to run into the same problem I have with the linkage. I want to keep my stock console and shifter. I can get some measurements that might help you. If you look at some of the pics I posted you can easily see the problem and the possible solutions.
Let me know if you need more specifics and I'll try and help.

Treblig