"1970 Pro Touring Dart Build"

That is from Super Scamp 340's build: http://www.forabodiesonly.com/mopar/showthread.php?t=130112
Maybe he will know a trick, or because he went flush to the inside of the frame.
Did you use a hex head bolt? Maybe a carriage type head bolt would clear?

It you decide not to use it, and summit won't take it back, let me know, I may take it off your hands for the original price.