Black pipe is fine. It is probably damn close to the steel the header is cast from.
Pick up one for your current size as well for $.79. You never know, the taper on it might go further out than your egt. Depending on the head on it, you might drill a cross hole in it and put a piece of safety/baling wire through and around the header for a while.
Don't over tighten a tapered thread. It it has enough bite, it might split that button in half.
__________________
I am a Commodore PET --- Now get off my lawn you kids...
|