Ruined the 1-3 top end of my motor?

[Miscou]

I've been getting a loud tap that sounds like it's coming from the the top end of 1-3 bank. I dropped the motor this weekend to investigate. I realized that I put the 1-3 scavenger oil pump cover in upside down the last time I had the engine out. I'd been driving that way for about 4500 Miles. The the initial tap lead me to believe I' had a worn a lifter. So, I replaced all 12 of the lifters on the 1-3 side. Now the tap is louder and gets even louder when car warms up. I put a stethoscope on the motor and there still a loud tap that is coming from the 1-3 top end.

Anyone ever made this error before and figured out what gets destroyed? I'm surprised I didn't get any warning lights or indications of poor oil flow from the car. However, it looks like the scavenge pumps only return oil to the sump. Hoping maybe someone can shed some light on the results of this blunder.

Any help would be appreciated. Thanks....

[Dick Shift]

Any of the replaced lifters show damage? If so corresponding cam lob condition?

[BYprodriver]

Be sure to pin engine at TDC & lockdown the cams before pulling off camcover. Hopefully the noise is coming from a lifter you didn't replace, but inspect everything.