Originally Posted by
tlracer
As a number of others, far more experienced and knowledgeable than I am, have said - it would make more sense/less cost to buy the right gearbox. However as I understand it that's not the question you're asking....
- If both engines rotate the same way, the gearbox input shaft will do likewise in either orientation
- If the input shaft rotation doesn't change, then neither will the output shaft
- If the output shaft rotation doesn't change then neither will the pinion
- The pinion location is fixed by the bearing location
So, what you'd actually need to do it leave the crown wheel and pinion right where they are in space, and rotate the rest of the gearbox around to the inverted position!
Practically what that means is move the crown wheel to the other side of the pinion, machine/replace sideplates, spacers, etc. as necessary to get it to all bolt together correctly and with the correct backlash, then invert the gearbox and work out what you need to bolt it to the engine, allowing the clutch to operate correctly, etc, etc.