I have a old long tail that was home made it has a 9 inch prop on it I would like to put a 8 x 4 on it .does any one sell a keyway prop any more thank for any info

Not stainless, Id just replace your shaft with the standard 3/4 x 10 threads and buy a prop from one of the major manufacturers. Think of it as updating the longtail.

A new shaft will cost you around $100 if you have someone who can cut you some threads and a keyway. I'd say its well worth it and you can get props from anyone.