1973-1974 RM21 vs RM23

[RR Fan Dan]

I was shopping for replacement glass and they had different quarter glass listed for a RM23 Roadrunner. My 1974 is a RM21 Roadrunner with fixed quarter glass. I believe that it is a coupe. My understanding was you could only get roll down quarter glass with power windows. Does roll down glass make a RM23 HT and fixed glass a RM21 Coupe? What is the difference between RM21 and RM23? Confused.

 

[YY1]

23 is roll down rear windows.

They do not need to be power.

21 is fixed rear windows. That changed through the years, from posts around the door windows and a completely different roofline, to simply different glass and no mechanism.

IIRC "all" 71/72 RRs were 23 body and "all" 73/74 were 21 body.