Exhaust blues, need advice----

Well thanks to everyone for chiming in! I just ordered a complete deluxe system from Accurate Exh. LLC. Talked to their engineering folks and they put my mind at ease that I will be getting the correct material for a dual exhaust setup for my 67 273. The system will ship today and I will be installing it this weekend if there is any justice on the planet.
Mighty happy about this my friends------:-) DR------------------