I have collected an early Bronco 9” for mine. I was told the 57 ford 9” was a little narrow for a 34. I have the 57 9” in my A coupe and it is a perfect fit.
I used a 9" 57 Ford rearend in my 34, I think its a perfect fit. I used an 8" out of a 67 Mustang in my 32.