Starrider,
Don't take this as an Ad or Endorsement, but I had exhaust systems done on the following vehicles: 1950 Chevy Fleetline, 1961 Willys pick-up, and 1964 Chevy C-10, all at the local Midas Muffler place.
Seems that their "limiting factor" was whether or not they had a "card" on the vehicle (spec-card?).
Where they seem to get hung-up is on Y-pipes for V-8s and some flanges for older manifolds.
There are some folks who advertise vintage exhaust in Hemmings; I bought a "Y-pipe" for a '61 Plymouth from Keppich Exhaust in Florida, and it fit...
You're probably best-off finding a local guy to do it, if possible- easier than shipping stuff back to the vendor if it doesn't work.