8) that depends. my 64 falcon 170 is an early production engine, and the later distributor does not fit. if you have a later production 170, then it should fit. as i recall it was a running change in 1964, so it can be a hit or miss kind of thing. if you have the early block you still have options.
1: you can purchase the early style dui system from classicinlines
2: you can machine down the distributor shaft below the gear
3: you can open up the boss that the distributor shaft rides in the block
4: you can contact addo, or one of the other aussies on this board, and get an aussie distributor
each of these choices has issues you have to deal with.
1: the dui system is rather expensive, but has the benefit of being a drop in replacement
2: if you machine the newer distributor, open up the boss, or get the aussie distributor, you have to convert to a 5/16" oil pump drive shaft as well as replacing the oil pump to the later one that uses the 5/16" shaft. in addition, if you modify the block or the later distributor, you have to be precise or you could run into other issues.