I wanted to respond to the questions regarding AP/Goerlich exhaust quick. Yes, I know that AP/Goerlich was huge back in the day as well as now. From the info that I'm receiving, I think AP was much more of an aftermarket company until they purchased Arvin and Maremont. Arvin and Maremont gave them a long list of exhaust assembly plants and allowed AP to begin manufacturing oem assembly plant systems. I am an older past Ford dealership master mechanic, and I remember looking under the first few 1992 Crown Vic's which had a strange looking muffler that AP produced. Ford continued using that same muffler on all Crown Vic's (less Marauders) until the Crown Vic was retired. So, I think AP plays a large roll in current oem exhaust production, but not in the 60's or 70's.......or even the 80's. AP was large, and they produced exhaust, shock absorbers, and many other components!
Interesting to note that AP produced an aftermarket muffler called the Golden Ram. It was painted gold ( imagine that) and looked virtually like an original Thrush. In addition, the Goerlich division of AP produced a muffler called the Roadrunner..........another Thrush look alike painted red. The Roadrunner mufflers were actually produced in Defiance, Ohio at the old Compo muffler plant which has been long closed.I suspect that many other mufflers and pipes that AP marketed were produced at the Compo Defiance plant.
I feel certain now that Walker was the primary supplier to GM/Chevy. I still have no idea about AMC or Chrysler in the day, but I suspect Arvin/Maremont/Walker?
There are plenty of holes in what I suspect with regard to oem exhaust systems. I'm trying to fill the gaps.......because I truly enjoy doing this. I can also now say with much certainty that Arvin was Fords main supplier for literally decades. I spoke with someone literally this week that knows for sure.
Just having fun,
Thx,
Brian N