Chevrolet Repair: knock coming from motor

Question
Hello and thank you for your time.  I have a 98 chevy 2500 5.7ch ltr. My problem is. Frustrating at best to say least i was changing my neighbors pcm out when finished i flashed it and found they a c.a.s.e.
Was needed to be preformed. During the test the motor started to knock so immediately stop the test and
Realized. The knock was coming from bottom end of the motor. Then remove the oil pan to inspect number 1,2,5,7 connecting rod bearing were spun so replaced changed out rod bearings but did not check out main bearings i only gave them a quick look. Put back together motor then ran fine no knocking in motor this time we went to do a crank shaft relearn drivabilty test before able to begin the test it start to knock again so attempted the test four times with no results. So replace crankshaft positioning sensor started the truck and now its knocking loud then before loud enough to make pause and think.it might blow have not done anything since

Answer
GOOD DAY MARILEE, WELL THERE COULD BE A FEW THINGS GOING ON HERE..YOU SAY THAT YOU REPLACED THE ROD BEARINGS BUT WERE THE CRANK JOURNALS OK ??? DID YOU PLASTIC GAUGE THEM ?? IT IS VERY POSSIBLE THAT THE CRANK JOURNALS ARE BAD OR SCORED AND THIS DESTROYED YOUR NEW ROD BEARINGS REAL FAST LIKE...THE OTHER POSSIBILITY IS IF THE MAINS WERE GOING BAD, THE OIL PRESSURE WAS GETTING VERY LOW WHICH WOULD TAKE OUT A ROD BEARING AS WELL. IN ANY CASE THIS ENGINE IS GOING TO NEED TO COME OUT AND GET IT REBUILD....I HOPE YOUR BUDDY DOES NOT THINK THIS IS YOUR FAULT BECAUSE YOU OVER REVVED THE ENG AT IDLE LIKE THIS TO RELEARN THE TIMING..I REMEMBER THE FIRST TIME I DID THE RELEARN I COULD NOT BELIEVE THAT YOU HAD TO TAKE THE ENGINE AT SUCH HIGH RPM FROM IDLE WITH NO LOAD ON IT TO RELEARN IT !!!  I THOUGHT FOR SURE I WOULD HAVE RODS COMING THROUGH THE BLOCK.. GOOD LUCK TO YOU,,,TOM.