Somebody cobbled up an exhaust system for my '70 Cuda and it was hung from straps screwed to the front of the rear frame rails. I have three 1/4 inch holes at the very front of each rear frame rail, some on the bottom, some on the sides. Can anybody tell me if there were any holes of that size there originally? I'd like to fill these, but can't remember if there was a brake line or fuel line clip or something along there that I may need a hole or two for.