https://www.energyparts-shop.com/en/...olite-66925379
Using compatable part numbers on this site I came up with this high torque starter for my 403. I'm happy with its performance and the manufacturer is a parts supplier for the US military so I assume they are kosher.
It was substantially cheaper than comparable high torque starters. Being an American engine I would presume they would manufacture a motor for it, Geoff