Vin code confusion

I'm trying to decode the vin on my 80 Mirada Cmx
xh22car180xxx
x=Magnum Charger Is this because they are Miradas forerunners ?
h=price class high
2=2 door
2=B pillar hardtop-I thought it was classed as a coupe ?
c=engine 225 1bbl slant 6- its got a 318?
a=last digit of year ?
r=Windsor production plant
180xxx = production sequence

Any help on my ?
Author: MoparTex