I've cobbled together a plate to hold the throttle motor. In the photo, the motor is just laying on the plate. I don't think I'll cut the plate to fit the belly of the throttle motor. I think I'll put it on stand offs. I've got quite a bit more work to do on the plate to clean it up like welding the corners and adding a rib for strength to the underside.
I left extra space on the plate for the vacuum manifold.
BTW, I had to remove the arm on the throttle motor and put it back on 180°. I also disabled the return spring on it. With the setup shown, the throttle motor rotates 20° more than needed to get full motion for the throttle arm. I'm planning to leave about 10° of motion at both ends and never rotate the throttle motor to it's limits. Make sense?