Back in the 70's and 80's, this man was "The Man" for high performance cycle parts. He made damn near anything needed to hot rod KZ's and GS's and even some lesser run bikes. Both Byron Hines and Terry Vance started their careers working for him. From his mentoring, they struck out on their own and started Vance & Hines...the rest is history. He ran a dual engine Top Fuel bike, then a triple engine T/F bike, and Honda V4 pro-stocker with an automatic trans., and even a V8 powered T/F bike. I think he even had a Goldwing engined T/F bike called the Battlestar-this thing was WILD! This guy was high tech for those days...everybody looked to him for the next great "thing"! He still makes parts but mostly injectors, etc. for import cars I think. Any parts you would need would have to be found used. If you have the old baffle, repack it with fiberglass packing. Many exhaust makers probably sell or can tell you where to get it. Most megaphones are similiar in size so possibly another make would work. I know Vance & Hines sells them as maybe Kerker may too(not sure about them though) as well as others. R.C. Performance pipes are great pipes and some guys prize them. I have one myself and have owned them in the past. Always worked and held up great. If the carbs are jetted for an open header and you repack it, you will need to lean it out some-added backpressure will richen up the fuel ratio some. If it wasn't, and you run without the baffle, the motor will run lean from less back pressure so richen it a little. I used to go up 1 or 2 on the mains and I think I raised the needles one notch on my smoothbores, so stock carbs may be different but should be close to this. Every header has it's own "sweet spot" so whichever header you use, run it and check the plugs. Carbs may be spot on or they may need to be adjusted some...it's all trial and error. I haven't tried it yet, but I am going to try a cone muffler core for car headers I bought from Summit Racing parts. I think you'd need the 4" cone but measure to be sure. Just get some new exhaust gaskets and replace them...that's all you need to do. Don't see why you'd need to replace studs unless the threadds are messed up. Nuts and washers would be a personal thing...new ones would look new. Exhaust flanges should be good forever unless you want to update to J-model flanges/holders which are smooth and clean up the look.Hope this helps.
1980 LTD (changed over the years), 1979 LTD (being rebuilt), 1977 KZ turbo and various KZ's in various states of build. KLX110