I have a bunch of those made up for different things I worked on over the years.Mostly just bolts with another one welded on top to make a T. I had them for Macks,(2 heads) Cummins,(3 heads)and Caterpillar,(one big head)John Deere,International,Perkins,Ford.I do have some made with bolts welded into old spark plugs for flathead engines.