Found my dads original 1971 duster!

Yep, that’s the right one, or at least one that works right. The throttle return spring bracket at the front of the motor is way wrong, but could probably just be bent to at least line up.

For your cable, try loosening the clamp on the throttle bracket and pulling it back as far as possible. Looks like it should work, so I wonder if you are just getting the adjustment wrong.
Good morning. Thanks. Ya, I have a bit of adjustment on the throttle cable it looks like! That’s my plan for this morning. I’m thinking I have to get that set perfectly before adjusting the kickdown linkage