1992 Grand am knocking

Iv, got a 1992 grand am and the motor started knocking at high rpms, The owner b4 me put a new head on it and forgot to tighten the cam gear, causing the cam to stop turning, when the pistons came up 3 valves where bent, i replaced the valves and drove it for about 2 weeks when the knocking started, i pulled the oil pan and its not the pump, it could possibly be a wrist pin or a rod, any other suggestions, this car is stressing me out iv been working on it more than iv been driving it. please let me know.....THANKS

I assume this is a 2.5. The oil pump assembly has a balance shaft in it that gets out of sinc when the timing jumps. I have seen this problem before, and the only fix is a new oilpump/balance shaft assembly, they are dealer only, and are $$$$$$$$$$