Factory tailpipes for 1969 models were 2.25" O.D. at the muffler , 2" O.D. mid of the gas tank (welded connection) and sized to 1-7/8 I.D. at the rear to accept chrome tips. 1968 models were 2" O.D. at the muffler and 1-7/8 l.D. at the rear to accept chrome tips.
Applications included both 340 and 383 engines. 1967 383 models had 2" O.D. tailpipes with turn downs at the rear as chrome tips were not an option. And yes there are reproduction tailpipes available that appear as original. Accurateltd.com. We sell a lot of them.