15x10 WHEELS ON A BARRACUDA

Well let's see the pictures then shall we? Because the AMD replacement panels are identical for the inner and outer wheelhouses. Same part #, same part. All the '67-69 Barracuda's, all the Demons and Dart Sports, all the Dusters.

View attachment 1715518436
View attachment 1715518437

I replicated your 14" measurement, the raised lip on the outside of the quarter doesn't change a thing for the tire clearance. The lip on the wheel house is what matters, so let's see that measurement. The frame rails are in the same place, so, if the inner and outer wheelhouses are the same part (and they are), then you're not going to get a measurement that's different by more than body tolerances.

Maybe @AJ/FormS has a picture of the measurement on his car, since I already made reference to his 13.25" distance from inner to outer wheelhouse, which is the same as on my Duster.
When you are trying to fit tires on without modifying the shape of the quarter you can fit a lot bigger tire on a Duster under the car. Trimming and rolling to the outer quarter lip still gives you 1 1/2 inches more total width on a Duster/Demon to keep them under the car. The bottom line is the barracudas are 1 1/2 inches narrower as I stated. That is a lot more room to work with. 3/4 per side.

Looks like you trimmed most of the outer wheel house off on the pictures of the Duster above. You won't do that on a Barracuda and still keep that much of the lip on the quarter