I have a 98 expo that is making a ticking noise by the right side by the exhaust manafold. local muffler shop found the back two manafold bolts broken off in the head they fixed this and the noise was cut in half. But said the head gasket was also blowing out exhaust. They ran a compression test for me, all 150-160 lbs. except one at 110 on the right bank. Ford said $1300 to replace head gasket. $3000 if the head has to be replaced. Has anyone had to replace just head gaskets and or heads? Truck has 150,000 miles, no water loss or water in oil pan. Thanks for any input.