01, heres the part number that I ordered. GM part # 12563964. I also have near 70K miles. Im gonna go ahead and do the oil pump and chain too. I do not want to have to tear everything off again because the pump went or the chain broke. Im gonna fill the pump clear full of assembly lube before I put it on.

 

01 i have a stock never used 5.3 oil pump at the house you can have CHEEP. it came off of my crate motor when i tore it down and yes i tore a brand new crate motor down. i did not use it because i used a ls6 pump. it is just an option for you.

i would personaly stay away from ported pumps because i have heard of more failures with them. that is just mho. many people have ran them with great success.