i believe i isolated the lower end noise to be the #1 cylinder rod bearing. i pulled the pan and all the main caps and the bearings and crank looked fine. i did not see too much metal in the pan so i cleaned everything back up and put the pan back on and filled it with oil.

the knock, only present when reving the engine, was not present when i pulled the plug wire for cyl #1.

i am going to pull the pan again this week and pull the cap for cyl #1 rod. if the crank and rod itself look decent what are the chances of slapping a new stock sized bearing in it and getting some mileage out of it?

was there anything abnormal in the oil pan?

I've done that trick with other cars.

Why not replace all the rod bearings?

If the rod is knocking, there is usually damage to the journal or the big end of the rod. In my younger days, I tried what you are contemplating with little success. Now, I pull the engine, put it on the stand where I can clean it well, and work in clean conditions. I let professionals polish or grind the journals and I take a lot of care fitting the bearings. That has worked out a lot better for me.

I tried that and it failed horribly after....30 seconds of runtime I think. I would think replacing rod bearings PRIOR to failure will work out alot better...but not after one.

Still...if the knock was present with all plugs firing, and not when #1 is unplugged, that would indicate (to me anyways) the bearing itself is fine...it'* the connecting pin in the piston that'* the issue.