[Hutch]

Welcome From Texas
The two most common are the Vintage Air and Old Air.
Both have the smooth firewall.
Use the search option at the top of the page to find previous posts on these vendors and subjects.
After having completely refurbished my original A/C and switching over to R134
I found I had about the same $ into it as I would have spent on one of new units and the new ones work a lot better.
Sounds like you are on the right track
Also the vendors listed on the Home page sell these units also and are more familiar with the chevy truck application of them.

Have fun