First off how do you measure it, are there specific points to use? I got 26 inches wide and 22 inches tall I believe which seems odd to me. It looks stock to me but I don't know. 72 duster. It did have an engine swap. I maybe looking into an aluminum one
You measure the core itself, (the fined area). They will be close to 18 high and 22 wide for a 22 rad. By the sounds of your measurements you are measuring the tanks and saddles with it. If your core is 22 high you may have a truck rad that will not fit a A-body.
Yes, the dimensions normally stated are for the core. I think your year was still 18"H x 22"W. If a slant engine w/o AC, it usually had a filler plate on the side, anything to save 5 cents. Maybe AZ slants got the full-width radiator.