To start, I have a 66 Dynamic with a 425 high compression engine.

I have seen this discussed before. But I was wondering what people here think about getting a duel exhaust by simply making a connection from the driver's side pipe that connects to the passenger's side and routing additional piping including another muffler on the driver's side. If I had this done I would get a muffler shop to do it. In addition to the new driver's side piping, I'd ask them to cap off the connection on the passenger side by welding on a cover plate.

I've seen that the "proper" way of doing this is to replace the driver's side manifold with one of those Thorton repro manifolds. Aside from looking stock, is there any major benefit to using the Thorton manifold?

Seems to me that a capable muffler shop can do this, but I am new to these cars and I'm not sure if there is something I have overlooked. Any comments would be appreciated.

Just another note: Ideally I'd have the time to get the Thorton manifold and make the duel exhaust closer to stock. This time, I am trying to get the car on the road... government safety requirements say I need to replace the existing rusted out single exhaust to make the car road worthy. I just wanted to check this option out, otherwise I will just get the single exhaust fixed up to get this car government approved. Desire to drive this car, lack of time, and lack of a heated garage are factors that come into play here.

-Rich

 

Get the proper manifold. It will make everything SO much easier and if a shop could do what you suggested it would be very unsightly and octopus like for piping. I dont think most shops would even try.