'65 A833 Backup Switch/Sensor Part Number

That same switch fits many years and models of transmissions including the A230, A250, and 435's in cars, trucks, and vans up to the early 70's. You might also want to try comparing your old switch to the later '70's switch. I don't know if it was just superceded to another number or if it's a completely different switch but the number is 3488270 and fits the same model transmissions in the early to late '70's.