That information kinda mirrors the O&R engines
Screw from the back early engines
Screw on from the front middle year engines
Then the screw on starters about 1970
It was media blasted. Im not sure with what exactly - and It's a TAS P-7
Here's my resto-mod today. You can scroll up above to my April 2018 post and see the before picture. The chain guard mold will be made this summer 2019 - then copies. I will later in the year make the seat mold and copies