I recently picked up another ln2 motor, thinking of trying an NA setup on my '91 cav. The motor has about 87k on it, and I had the opportunity to drive the donor car just before the reg was pulled. It ran and drove very well. yesterday, I pulled the head off the motor, and in the process, I was a little bit surprised to find that one of the head bolts, (the one closest to the transmission on the front side of the engine, not the one under the valve cover), was really, really, really muddy, I would say even somewhat deteriorated. I see no evidence whatsoever that the head gasket had leaked, so it seems clear to me, that the water jacked has intruded into this bolt hole. so my question is, is this common on these motors? and should I just put sealer on the new bolt, or should I have other concerns I need to address before I go ahead and use this block?