[BruceLambo]

Mark. In your last post, you say that you have mentioned about changing the 5th gear ratio. What you have said in your post relates to the final drive (crown wheel and pinion). You have a 369 gearbox that has a 3.89:1 diff ratio. The other desirable ratio is the 3.44 which is available in the 21 turbo and Alpine cars. The standard 5th gear ratio from your box is 0.89:1. There is another ratio available which is the 0.76. This is from the V6 Turbo models and the Lotus Esprit V8 box.
My thoughts on it are: it might be a good crusing ratio, but if you are flat out down the back straight of a racetrack going from 4th to 5th you will slow your accelleration due to the ratio gap - you want to keep accellerating, not go into cruise mode!!! My second 'opinion' is that because the 5th gear is overhanging with only 1 side bearing support, there is more 'thrust' available between the higher overdrive ratio gears, effectivly pushing them apart easier. I feel that 5th gear is the most stressed gear in the box because of this. (Thoughts and theories welcome on this)
I have had various engines hanging on both styles of gearbox (369 and UN1) and the only change Id make is to narrow the 1st and 2nd gears. One car I had when testing, I clamped a video camera on it to do 'chassis looking' views, and when you see how it performs with the standard ratios, its not really worth the change. I should find a way of posting it on here so you can see and hear the box in operation.

Oh and while we are talking input shafts, I can see how things broke. The splined end of the shaft really just 'sits' unaided in the sleeve, so when you released the pressure plate, the clutch plate would be litterly 'hanging' in the breeze!!! A lot of the Japanese front wheel drive cars have their boxes like that, but they have a very short 1 peice input shaft with suitable shaft support bearing. It would be quite easy just to put another 'longer' shaft in that gets into the spigot bearing.
There is a guy here in NZ that has a GT40 with a 350 chev in it (webers, blah blah) and a 369 box. Its been dynoed at 450hp at the rear wheels with similar torque figures. Now he hammers the hell out of the car, and has never had a gearbox issue.