5.o MCM, came in for general service, found manifolds and elbows rotted off rubber coupler. Ran compression test and found #5& #7 had 85 and 110 lbs and rest were at 185. Minimum valve job required. Flame arrester has no engine numbers on it. My question is do I change head bolts when replacing heads? The manual shows torque to yield specs but doesn't spec replace head bolts. I have changed many head gaskets on newer vortec motors in trucks and cars over the years and they always spec new head bolts. Are these different head bolts bein marine application? Raw water cooled so I will be using marine gaskets on heads, not even a question. It is approximately a 2005 Wellcraft and has bein sitting a few years, tried running on muffs a little bit to see if maybe had stuck valve and running would free it up, nope. Any advice would be helpful.