It was over 40 years ago that I ordered a CAT exhaust system for my '66 Tiger. The car has been garaged the whole time and is now being restored. I was pleasantly surprised to find out that the good old CAT exhaust pipes are still usable. No holes or areas weak enough to prevent use. The mufflers are not usable. I plan to replace the CAT mufflers with Flowmaster HP-2 18" (total length of 24") mufflers as they appear to be a good fit with these old pipes. I will coat the old pipes inside and out to protect them as best I can. With the limited mileage that I will add to the Tiger I think the old pipes will be fine. Picture of system before any cleaning is attached.