out of stainless ? are you out of your fucking mind ? do u even know what sced 40 is? that shit is fucking thick , if ur doing mild then yes, but if its out of stainless?have u ever built a manifold? i dunno maybe you like to have a 85 lbs header , maybe when u have some time u can come by the shop and look at a sced 10 elbow and see how thick they are , i thinkk i have few peices kicking around from the last manifold we built , maybe you should contact , hks, greddy, full race, aps and everybody else that makes turbo manifolds with less than sced 10 and let them know how it should be done, back purgeing is not necessaryin all cases, especially on something as thick as sced 10