Johnson 1979 35hp head bolts one stripped

"I bought a boat and 1979 John

"I bought a boat and 1979 Johnson 35hp engine , it had been sitting for a year , the previous owner had died.
I rebuilt carb, pee hole completely blocked, unclogged it , replaced thermostat, went to check head bolt torque, all tight except one , just kept turning, I removed the bolt, no signs of metal in threads like it was stripped

.. are the bolts in this head different lengths ?

Im gonna jerk the head and check the head for warping, and check the hole for signs of stripped threads, Im assuming I can just heli coil if it is stripped ?

Thanx in advance
Sean"

"those bolts,are all the same

"those bolts,are all the same...u can heli coil....some people,have better luck w/heli coils than others... myself, i take to machine shop,and fix it,instead of patching it...or tap to larger size maybe."