I spent most of my spare hours this week wracking my brain for a solution for the motor mounting problem. I finally bit the bullet and drew a very accurate SketchUp model of the AC55 motor, plus a drawing of the new motor mounts & bushings. I also carefully measured the distances between the motor mounts, as well as the angle of the motor (5 degrees). Using all this information, I figured out a motor mounting scheme that, although a little baroque, I think will work very well:
Here is just the left side, from behind. The new mount has mirror-image left and right sides. Each side is composed of two parts which swivel about a large 1/2" bolt. Below, you can see the two parts - one of them is bolted to the motor mounting point, and the other gets bolted to the motor. This pivot allows some adjustment to be made to the motor angle (I'll probably also enlarge the hole that the pivot bolt goes through to allow for some adjustment). The two halves will be welded together, but there are 1/2" bolts on the part that attaches to the motor to give it more tensile strength:
Here are a few exploded views of all the parts. Once I get this built accurately, I'll take final measurements and update with a PDF drawing of the assembly:
Tomorrow promises to be warm-ish (55 degrees) and sunny - perfect welding weather... hopefully I can get this completed in one day.