Exhaust Manifolds with Dynomax Mufflers?

I have a 71 Duster 360 auto w/ 3.23 rear and a 340 grind cam. It has 340 HP manifolds, Dynomax turbo style, TTI 2 1/2in full exhaust w/ H pipe. It was a lot louder than I expected. Especially about 50-60mph. Not as bad at freeway speeds above 65. It was annoying trying to have a conversation. It was bothersome enough that I put a set of larger Flowmasters for a SUV trying to quiet it down.(160$) It didnt help. I am still looking for a quieter set but havent found any I like yet.