.620 mechanical Purple Shaft?

Also not going with E85 any more...

Mainly because I don't trust I'll still be able to get it with the way the world is going.

So I ditched the 915's and bought a pair of old race ported 452's. Should make my compression 11.5-1 so I can run it on a Shell 93/Avgas mix. I live only a few miles from a airport that sells it.