On my family vacation and on a 5 hour run yesterday I noticed my oil pressure on my stbd main engine had dropped apprx 10 psi at cruise. This was on a VDO gauge at the helm. Wasn’t too concerned thought maybe gauge was messing up but went down in ER to confirm and sure enough the engine room gauge reflected about a 10 psi loss. Now I have gotten concerned. Boat is a 1995 Viking with 820 hp 10 cylinder Mans. Cruise Rpm 2050 and oil pressure is normally 80 psi and has dropped to 70 psi. These are mechanical engines with no computer. All else appears to be normal. I have visually looked at the oil but that reveals nothing to my eyes. Would rather not deal with a repower right now. But hopefully getting ahead of myself. Also headed North from Key West. Does anyone have any thoughts on Scott Marine Power in FLL. Thanks for your time.