The more I do, the more I find out.
1. I have a right handed propeller.
2. I have a contra-rotating gearbox which means I need a left handed propeller.
3. The Perkins 4.108 engine has non-standard face plates at either end.
4. The original engine mounting brackets are all wrong and need to be made individually to fit.
5. The propeller shaft coupling plate is mid- matched to the gearbox coupling plate (two holes vs four).
6. With such a mid-match I cannot get a flexible coupling to fit between the gearbox and propeller shaft.