I have a 67 SS350/RS vehicle. How can I tell if I have the correct motor mounts and brackets? I just received a Gardner exhaust system (dual w/resonators) and the right exhaust pipe from the heat riser is line-to-line where it passes under the transmission mounting support.

The rest of the right bank is OK. Left bank is perfect in every way!! Although I can send the pipe back to Gardner to have them check it, I want to make sure other things which could affect the issue are correct!
Also, what is the correct posi tag ID on the rear axle? I have a 3.31:1 and have both the stamped metal tag that goes on the cover pan and the red plastic filler plug (1 inch) tag? Also, which bolt does the metal tag go on if that is the correct one??
Thanks... Dan