The rod bearings are an Achilles heel of the SHO V6.
They can be replaced with the engine "in-car" as a preventative measure (strongly recommended), or during an engine rebuild/overhaul.

Please check your clearances with Plastigauge or a micrometer.
If you have a severe rod knock, it is likely that your crankshaft will need to be machined (and "undersize" bearings used) to return clearances to within specifications, and/or the connecting rod "big ends" reconditioned/resized to obtain proper bearing "crush",  which is what holds the bearings in place and keeps them from spinning (not the locating tabs).

The main bearings do not tend to wear as quickly as the rod bearings in the SHO V6,  but replacing them is also a good preventative measure and can help to restore normal oil pressure.
While slightly more difficult than rod bearing replacement,  the main bearings can also be replaced with the engine "in-car" (or during an engine rebuild/overhaul).

Please check your clearances with Plastigage or a micrometer.
If you have a severe lower end knock, it is very likely that your crankshaft will need to be machined (and "undersize" bearings used) to return clearances to within specifications.