I didn't do a very good job of explaining this before, hopefully this is better. The picture of the nuts shows them finger tightened, there is no head gasket in place. You can see that the nuts only go on half way. I pulled the studs and remeasured and they are what the parts catalogue says they should be. They were all seated properly. Only the 4 6066 studs are long enough to use. Measuring through the stud holes, the top of the head is 1.937" thick, the bottom is 1.25". Are these heads for some reason thicker than others? Are there longer studs available? Would appreciate any help as I am stumped.