Thanks, guys, for all the help. Based on what I have learned from you all, tomorrow I start surgery on the A/C cabinet. As of today I have found two brands of 8000 btu units that will fit my 2000 RT 190P. They are made by Sharp and Kenmore. All others are either too big or have lower btu. The Sharp is a good bit smaller than the original Fedders in all dimensions. The Kenmore is exactly the same height as the old Fedders, but smaller otherwise. They both have hard start capacitors, but not the kind recommended by RT service.
I'll bench test on the genset before installing, and make sure the tilt is to the rear. By the way, I have the instructions for a/c replacement as supplied by RT service if anyone wants them. It is an illustrated PDF covering 170 Popular Dodge, 190 popular and versatile Dodge, and 200 Popular and Versatile Chevy. Email me at anthonyarnold5170@att.net and I will forward. It seems, however, (based on actual experience in this forum) that the instructions go overboard on the need for a hard start capacitor.
More later as the project progresses!