1966 engine with 1981 904A

I would be worried if it were the other way around and they used a later motor with an early trans. But your situation sounds like someone already remedied the mismatch!
Cosig- 65 barracuda said I should PM you about parts but your mailbox is full. This is the only way I thought of reaching you. I live in Michigan as well. Pm me if you get this.