Deleting EGR system from a 420 SEL. Would anyone know the thread type and pitch of the threaded female hole in the exhaust manifold? Just from inspection it's a fine "bolt" or straight (untapered) pipe thread. This same thread type is common all over the engine. Detroit irons always use a standard tapered pipe thread (NPT). Just wondering if they use a bolt, or straight metric pipe thread? Have sone other things to plug and this would be useful info.

TIA, Dave