Uno99, I'm working on the same problem. 99 GTP with a rod knock. Spun #3 crankshaft journal / connecting rod bearing. Viewed the forums and it seems rod bearing failures are common. Did you find any other thing that might have cause the failure?
The engine I'm working has a worn camshaft bearing. It's worn down into the copper babbit. Could have caused oil starvation at the rod journal. I have a picture of the bearing, had trouble uploading.