The automotive machine shop where I worked part time for several years had a BIG belt sander, with a belt over a foot wide and a bed four feet long. It came in very handy for flattening out warped manifolds and other parts that needed to have gasket surfaces trued up over a wide area. It's been debated several times whether to leave the intake and exhaust bolted together during such a procedure. I prefer to loosen the bolts slightly to let the manifolds find their closest common plane, then hit the belt sander with the complete assembly.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!