another header leak

i got a 360 in my duster and the headers leak no matter what. when i installed my cheapo flowtech headers a few years ago i put them on the big belt sander at work and made them true. the head mating surface was clean and true as well. my boss told me to use high temp rtv but i didnt. instead i used the cheap gaskets that came with the headers. they blew out within a month. then i installed a set of the standard felpro gaskets, same thing. they blew out in no time. then i bought the copper mr gasket gaskets and they didnt seal up at all from the get-go. should i try doing the rtv method? i read about a gasket that everybody on here was recomending (cant remember off the top of my head. it started with an "R"). also, my collectors are leaking too. the jackhole that did my exhaust bent the crap out of the flanges over tightening them. is there a remedy for that other than new flanges? thanks.