Thanks Brian. That conversion is partially done. I made a template from the parts car and cut the portion of the hole that comes out of the existing panel. We will wait to weld the "fill piece" into the kick panel until it comes back from blasting with nice clean metal
As for the piece that has to be welded into the firewall in that area, I've cut the required hole in the firewall to receive it. While the body is away being blasted, I'll harvest that piece from the parts car, get it blasted and ready for installation into my car. Looks like it should be easy to locate by bolting the A/C air box outside the firewall into place, then attaching the harvested piece to it. That will determine where it gets welded.
The other holes were not that difficult. I took my time, checked and rechecked my templates and locations, then made rough cuts with a recip saw, followed by final, careful cuts with aviation snips. Thanks Loren for that tip!
After cutting all the holes and drilling the required mounting holes, I test fit each of the pieces of the A/C system and they all fit well. I was glad to find in that process that the design of the system allows for some degree of misalignment. As we all know, manufacturing tolerances weren't all that tight back in '65. I think that worked to my advantage in my role as "shade tree mechanic"!
Thanks again for your advice and parts! I've still got a ways to go with correct lines, dryer and POA valve updates, but I'm happy to have this stressful stuff behind me.
Oh, and on the subject of parts, I was able to sell my '66 aluminum valve covers and purchase a nice set of the correct covers for '65. Onward and upward!
Chuck