on the 84 cougars is the speedo control cable or eletrical? and if its cable then i can use a mustang speedo correct? or even t he entire cluster?
1983-84 cars have cable-driven speedos, yes. In 1984 there is also a VSS that sends speed information to the EEC-IV computer. That is the only electrical part of the speedo, and only for 1984; it does not affect how the gauge reads. You could technically use a Mustang speedo/cluster in your car. It would have to be a 1979-89 cluster (for use with a round steering column; from 1990-93 the columns were square to allow for the airbag). Not sure of the fit...thinking it will be way too large for your dash.
so what would actually fit in the dash? anything off of a mn-12?