I need to get some custom half shafts made. Thought about welding some up but I don't like the idea of them busting at speed. Sure would make a big mess. Anyway, how to you determine the correct length? Anyone got any links to info on this?

Paul, I think Rorty posted some good info. on this topic on here somewhere.

I think it is a case of finding minimum length position (i.e. shaft horizontal) and allowing about 1/2" of float IIRC.

Worth a search I think.