On the non a/c A bodies ive noticed that some have the wide black ring on the firewall that bolts to the blower motor & some dont. What years had them & what years didnt or did all non a/c cars have them ?
IIRC, The sealing ring is on the inside of the firwall on cars with 3 stud mounting (newer). The black ring on the outside of the firewall was used on units with 4 stud mounting.