Russ, small problem, even if the input shaft would fit, which I feel sure it will, you still have a GT6 clutch plate, because of the splines on the input. You can still add the pressure plate from the TR6. Since you have gone to a lot of work making the Spite 6, why not use the front casing off the GT6 tranny and figure a why to add a Ford T5 to the back end of it. Just a little dream I had, even saved a GT6 bell housing, just in case I ever get time.
Wayne