i have a collection of hammers that would amaze you. bluewrench applied to stud bolts, pull the header pipe---EASY WITH THAT RATCHET EUGENE! THEM STUDS BREAK EASY! actaully i like to heat the manifold and replace the studs---but that's me, anyhoo--check position of the scrap metal flapper---then do the deal. oh yeah---mid range whatzit. guess that means headers and the vette manifolds i got with no heat riser don't work. the concept of the riser was good in theory, but not very good in real life. were more of a pain than they were worth, and most guys, including me trashed the goofy things. different guys got different ideas--this was one of the first, and most feeble attempts at pollution control--heat the manifold to better evaporate the fuel---o.k.--why do racers use cool cans? cool