[RichardJ]

You said "non threaded studs" in your last post. To repeat what everyone said and to make sure it is clear, those end guide pins are threaded into the head. Every hole down the side of the head is threaded 3/8-16. The heads originally had those end pins and the third hole from each end had a threaded stud for a 3/8-24, nut.
I put studs in all eight holes and it makes it a lot easier to hold all three pieces and the gasket in place for assembly. In the picture there is not one nut or bolt holding the manifolds. They are just resting on the studs.