I have headman headers that are coated without flanges. So what is the best way to attach mufflers? Should I weld them on? Or are the mufflers bands any good?

I use the bands, but I use them only in a temporary situation - to street test drive. They actually seal quite well.

I have used the bands, and they do work, but get the step style and have the pipe expand to go over the collector. Thats what I did, and never had a problem with them coming lose and or falling off..

Thanks for the info so far. Want to go with a quiet muffler. Any suggestions on a muffler that is quiet?

You going to sneak up on the competition

I like my Dynomax 6" round muffs FWIW

I slid the mufflers over the headers and drilled two holes in each and ran screws into them. Just unscrew the two screws on each muffler to take them off

Did the same thing but I used pop rivets instead of screws. No crush on the muff.

There is a darn near local to me outfit ( hearttthrob exhaust )that will custom make pipes for you....I plan on having them whip up a slip on pipe for the 3 1/2" collector and weld the muffler to that.
I am puzzling over necking it down to 3 " or not , but plan on about 3 feet of pipe before the muffler with turn downs pointing at each other to try and attract a little less attention on the street.
Something about cancelling frequencies I read once...if I am misguided in my thinking , when you're done laughing , correct me.

I used band clamps with tabs welded to the frame to hold the exhaust up

I ran the Magnaflow race mufflers and the Pypes Race Pro mufflers, neither slowed the car down at all and sound nice!

Thanks for the info guys. My collectors are 3 1/2.