a different exhaust question.

[slapthefunkyfour]

Tonight I'm gonna weld up the exhaust for my 66. I just barely finished the new 350 transplant, and started it for the first time last night. Before I spend 20 minutes breaking in the cam, I figured I better put some mufflers on so I don't piss off my neighbors.

I bought some exhaust pipe from the local master muffler to use. From what I can tell, it is the exact same thing as EMT(electrical metallic tubing). Is there really a difference? I think that EMT is galvanized so I really need to hold my breath if I weld that stuff. I could be wrong.

So my question is: what is the difference between plain old exhaust tubing from master muffler and EMT?