exhaust? or inlet? i.e. alloy or steel?

there is some good sprays these days that will loosen bolts up over a bit of time, an "easy-out" is really the only way then still... why is that not working?

Hi all got a manifold with a snapped bolt inside the manifold! As in no bit protruding..Try as I might I cannot get the broken stud out.. High tensile drill to drill a pilot hole for the screw extractor can't get it out.. Tried heat.. Still won't budge!

Just wondering if there were any other tricks!

Thanks so much
Tom