Re: MIE and R model designations
MIE = Mercruiser Inboard Engineering (or engines), Straight inboards only
MCM + = MerCruiserMarine. Sterndrive engines
R = Revised, this is for the drive only. The original drives were called
#1 drives or they were designated by the motors HP. On an old boat (pre 67ish) a 120 engine would have a 120 drive on it (even though it was the same thing as a #1 drive) R drives ran all the way up untill the mid 80's I believe when there were some changes. You can DL the drive charts in the DIY section and read about the history of the alpha drive.
