update to all, I was able to find my old pipe bender from the 1990s and he expanded a cheap set of header adapters and they fit pretty good. I fabricated a few fittings and was able to install the 3-inch Magnaflow system I had left over from a 1972 El Camino that was totaled. The fit is pretty tight, especially over the Currie 9-inch but it looks real nice. I tried all suggestions and a simple expander worked the best. So close to firing it up