The heater boxes changed over the years. I used the range 83-86 for
replacing an 82 because that is the simplest upgrade for the trouble
prone 82 box. Any box from 83-86 is plug compatible with the 82. The
even later boxes can be used as well but more is involved than just
pulling the 82 out and putting the 87-91 in. Not hard by any means but
more to it because of the change in side hoses on the box beginning
during the 87 model.

Mark

Jim Felder wrote:
> Mark,
>
> Does this mean that an 83 is like, say, an 86? Is an 86 like a 91? I
> seem to remember some differences in the box, it may be different on AC
> cars but not sure.
>
> Jim
>