I need to order some tubing, so I need the outside diameter of the metal plates, that retain the front spring islolators. It is at the top of the shock tower, and is retained by the same bolts that retain the shock mount. On later cars, these are welded to the the body. My car is together, and has to stay that way ('cause it's parked on the street), and it's raining sideways at the moment, and dark.
Had spacers on top of coil springs on my 64 Falcon. They were 5 1/2 od and fit ok. Coils are out now, can measure up inside later, after work.
Sorry about slow response, having internet issues. The d shaped piece on top of the underside shock tower. It's 5 1/8 at the radius.