Rear Speaker/Defogger Housing

Bob Wilkie said
The 70 swinger has the 6 x 9 speakers oriented lengthwise across the package tray in the same manner as the E bodies. It looks like your 6 x 9 opening is lengthwise oriented front to rear which would explain the need for adapting. I think I will be able to more easily make it fit then you did but I have been wrong before.

Yes that will be helpful. Just watch out for trunk hinge support bars.

And note that green car has the speaker in the wrong hole.

Does your package tray have that little bump to accept that stabilizing bracket?