How about posting a few pictures of that original 75% exhaust System you removed? The factory 1968 H code exhaust system was a one year only exhaust system that was pretty restrictive. Had about 34” of 2-1/4” pipe up front and the balance of the system in 2”. And then exiting through 1-5/8” chrome exhaust tips. 1969 exhaust systems were better flowing upping the pipe size up front and partially increasing the tailpipe size to 2-1/4” and 2” back sections but still retaining the 1-5/8” chrome tips. But the pictures will be educational showing how crude the original factory exhaust was fabricated.