It really depends on what transmission and engine combination you are talking about. I have a 1964 Galaxie 500 XL 2dr with a 1970 390 hooked up to a stock 1964 Cruisomatic trans which is the large 3 speed with green dot drive. If your engine is a 302 then I suggest a C4 trans. The big block cars should all have C6 autos or 4 speed in those years. It is much easier to swap an engine around in those years than a trans because of the difference in years. The engine will bolt up but it might have problems clearing the firewall along with the correct tranny mounts and cross member. You would need the existing bell housing from the 70 also. What engine and trans?