I have a 71 240 and a 75 280 AC car, the 71 has the Civic blower in it
and it whips up a storm compared to the 75 that has the stock AC. The
civic blower is one wire but has the speeds controlled by the blower
switch that must have resistors for the different speeds. Here is a link
to info on both the Civic and Ford heater blowers.
http://www.zcar.com/forums/search.php?f=1&search=civic+blower&globalsearch=1&match=1&date=0&fldsubject=1&fldbody=1