Exhaust Mount off Getrag
Assuming your five speed has used the two ears halfway along for the crossmember support. At the back of the box, on the right hand side, pointing to the rear is another support ear or bracket. In my installation the two exhaust pipes of the downpipe pass directly under this ear. I used a piece of threaded rod mounted on this ear to support the exhaust as follows
The original supporting arm for the downpipe pair had an upper and lower clamp, with curved surfaces to locate and hold the pipes. A bolt passes through the upper and lower clamp, and between the exhaust pipes, holding them. I cut the clamping parts from the arm and drilled the bolt hole in the two to open it for the threaded rod.
The threaded rod is attached firmly to the gearbox ear by a nut and washer above and below, and likewise to the clamps around the exhaust. Adjust the nuts to hold the exhaust firmly, but without introducing any stress.
The attached JPG may help. It will certainly help you understand why I didn't last long in the design office in the days when these things were drawn by hand.
If I were doing this again, I'd use a gearbox rubber mount on the gearbox ear and an internally threaded tube cut to the correct length to extend downwards to the clamp, with a bolt upwards through the clamp.