Hey guys, I recently developed a slight grinding noise coming from my 76 35hp Johnson. To me it sounds just like the whining in the rear end of my 63 Ford pickup. My first thought was that it was the lower unit. It a rhythmic whine, kind of a"wyooowyooowyooo". Oil in lower unit seems fine, no filings or grit.

I've had this motor for only a year or so, very well maintained, however it jumped outta forward under load. Researched repair for this and found some say flip the clutch dog, others recommended replace. I don't rely on reverse much so I flipped the dog and now only slips outta reverse occasionally. All else in foot seemed good, bearings felt fine, New seals and back on water. I don't think this would cause the noise but....

Not sure how to go about diagnosis on cause as I only hear it on the water at mid to high range.

Compression and even 110 on my gauge. I've not pulled head to look at cylinders to assess wear but may do that later this week.

Kinda feel noise is from upper bearing, if this is case, should I expect full rebuild?
Or look for another powerhead?
Can I use a different year powerhead, say, up to 79 if all electrical, is switched out too?
I would appreciate any and all input, Thx guys