Brother of The Benz, MikeV
Larry called the shot, get your little grubbies on a Service manual before you make a mistake that will cost plenty bucks.
The small plug that is removed by screwing a bolt into it's threaded ID is straight forward, the kick in your breeches is MAKE SURE THE THREADED END IS FACING OUT WHEN REPLACED. If not it won't be removeable the next time.
Whiether you leave the manifolds on or off the head is your call.
Most important, beg, borrow or steal a manual and save some heart aches.
Hi Larry long time no hear.
Happy Trails beep beep from The Spiderman in Houston!!!