i had 20-30 headers and exhaust systems done by a powdercoating shop in burlington wis,you need to do this to new parts and cem wash and sand blast them first,them coat the inside and outside,they look shiny ,till you fire up the engine after that they look like satiny aluminum,you can pour gas...
try the ARP stuff,and don't use a wire wheel to clean threads,,ive done a ton of big block chevy boat engines [they have head holes into water jackets] and this works
if your going to re-open up the eng,first wash the studs and holes out with break-kleen,then the holes should have a clean-out tap run thru them[not a thread cutting tap-as it makes the threads to big],,then use ARP sealent/lube and run studs in by hand,newer studs have an allen hole in...
try using 2 people,1 to push brake pedal,2nd to open breader,,start by opening breader-then push brake pedal to the floor slowly-then before letting up pedal close bleader,,,repete steps 4-5 times or no air comes out and clean fluid comes out too,,make sure not to run master out of fluid ,,,i...
i used to run it,but now i run the ''walmart'' brand 15-40,im told its made by mobil and is the same ,just a walmart label[on the diesel weekend talk show on xm radio]