Removal and replacement of the expansion valve was successful yesterday. The technique used was similar to Bob's concept of heating and wicking; we used a small propane soldering torch for heating and liquid penetrant for wicking applied to the flare nut on the evaporator inlet pipe. (The hose-end fitting on the valve was not stuck and the hose had been previously removed).
After a few heating and wicking cycles, the flare nut fitting finally broke loose. We used a long wrench on the flare nut and a second wrench to secure the valve while breaking the fitting loose. (Shock tower brace had been removed). The new valve was installed, system filled with R-134a and Select-Aire is now working in the car.
FYI, the removed expansion valve has C5OA, 19849A, 436 and FoMoCo inside rectangle stamped into it. Don't know if it's the original or a service replacement.
Thanks all for your suggestions.