91 z24 engine problems

i am 16 years old and looking to do some performance tuning to my 91 cavalier but first i have a clunk in my engine i have already replaced the rod bearings and there is no metal shavings in the oil
i am thinking more towards the timing chain if anyone has tips or has had this or has any other ideas please help me out
thanks

How many miles are on this car? And how well was it maintained? OHV engines are famous for pushrods clogging their oiling holes on poorly maintained engines..... also could have collapsed lifters.