I am trying to salvage a head which was welded and I machined out to accept a precombustion chamber.I have about a dozen but they are all bigger than the ones in the head i,m working on.The ones I have are 1.260 in dia.(1 1/4 ) and the dia I need is 1.176 in dia. ( 1 3/16 ).I think these might be from a 1500 head?Any one have any of these? Jim