Technical What year suspension is this?

Although it is overkill for strength, the 9-inch out of a truck application will have your 5x5.5 bolt pattern. Early Bronco is popular because of the width, but being fenderless you have a bit more flexibility.

 

The rear in my 31 sedan is a 67 f100 and with the right offset wheels it fits great. Federless car though. With fenders it would probly look wrong.

 

Under construction shot. Here it has reversed rear rims. Since changed to 8 inch rear wheels with 10.5 inch towel city slicks.

 

Agree, the rear end is '40 car or '40-'41 pickup. The '41-'48 rears have a longer torque tube, along with shorter radius rods that bolt up further back on the torque tube. The earlier rears have longer radius rods that attach closer to the front of the torque tube. The front is '42-'47. If you were closer, I'd like to have that front wishbone/spring hangers/stabilizer/sway bar, but shipping costs would be prohibitive.