Manual brake push rod

318 car? Stock (8.25") rear? Haven't you considered upgrading to later A-body (BBP) discs with larger axles in rear?
I have considered that. I do have that setup on my 67 Dart GT. I have a decent set of Rallye wheels on it now, and didn't want to really have to replace the wheels and tires right now. I did convert to an 8 3/4 rear.