Perley,
The bend in the top bar of the rear radius rods is there merely for body clearance. Without the bend, I would have had to raise the rear of the car up (NO! Never!! ) or cut a notch and some of the floor out of the body. Also, from a structural standpoint, the bottom bar should always be kept as straight as possible so that it won't bend under acceleration. When you nail the throttle in a car, the pinion gear tries to climb up the ring gear. That causes the rear end housing to try to rotate upward, pushing the bottom forward. If there is any flex in the lower bar it will cause wheel-hop and eventually metal fatigue and breakage.

I always set my pinion angle down a couple of degrees so that the front bearing on the pinion gear will get lubricated. About ten or twelve years ago, on the 8th lap of a 10-lap heat race, the pinion gear assembly, a piece of the carrier housing, and yoke came out of my stock car with half of the drive shaft still attached. I was told that when the pieces hit the track, the remains of the gear and bearing were glowing orange-hot! (This was a 9-inch Ford rear) When it happened, it sounded like a cannon going off inside the car and the front half of the drive shaft cut a gash in the floor and tunnel about 3 inches from my ass. When the pieces cooled off, the gear teeth still looked fine, but the front bearing was melted together and showed no trace of oil. When we checked the pinion angle later, it was pointed up about 5 degrees. Since then, whether it's right or wrong, I have always set my pinions tilted down a couple of degrees to keep the pinion bearings lubricated and have never had a similar problem.

Bobby,
Thanks for the info. I will look at some Mustang shifter kits. I know that Ford and GM used some of the same 5-speed trannys, but it hadn't occurred to me that the 4-speed shifters might be the same or, at least, similar enough to interchange some parts. Thanks again for the suggestion and for spending the time on my behalf.