Hi guys, I just bought a 93 celeberty with a 4.3 mercruiser. I bought it knowing it needed work, exhaust manifolds and the starter reinstalled. I reinstalled the starter and checked the compression (before spending money on the new manifolds) both sides had one about 150 and the others were between psi 30-60. I put air to each cylinder with rockers removed, not only did I find leaking valves but it caused a slapping sound, like something was loose in 2 of the cylinders. Nevertheless the motors out and on the stand and ripped down with no major signs of something wrong other than a few stuck rings. Has anyone rebuilt one? Or is just as cost effective to buy a reman longblock?