starter motor for slant six

crooked1/2dozen said
SSD:

"-'63-'66 Canadian-built vehicles used Prestolite ("Auto Lite") direct-drive Bendix drive starter"

I'm nowhere near my car right now and can't check it, but it sounds like I have a direct drive.

Yup, your '64 Canadian Valiant would have a direct-drive starter. Sounds like this when cranking. (that's my '65, now departed, recorded long ago).

I can get a Nippondenso starter from him, sounds like they are gear reduction and won't work on my '64 225 Valiant.

Correct, it won't work on your '64unless I sell you the one and only special adaptive starter drive I have on the shelf for you or your local auto electrical house to swap into the Nippondingdong starter so it will crank your car without changing the torque converter or flywheel (as applicable). Send me a PM.

are there any other smaller, lighter and more powerful starters that might?

There are custom-built mini starters that cost a whackload of money.