8.75 rear shock ubolt plates

I measured the axle tubes on my '67 Dart 7.25 and they are 2.5 in. outside. I also measured an a body 8.75 housing I have and those tubes are 3" outside.

See attached photo...

If the measurement between the white lines is 3", then it will fit an 8.75. If its 2.5", then it fits a 7.25.

Like I say, I determine 7.25 plates from 8.75 plates by the shape of the contours in the plate itself.