Just new to this page or site and seeing what's what

So , I have a 4.0 liter inline "buzzin half dozen" 6 " silly-nder in my 97' ZJ Lar-e-do 😂 I believe it's needing a good overhaulin or SOLD AS IS 😂 JM I LOVE TO HATE IT BUT , the 4.0 liter is making a screeching as if metal on metal noise and it's not the distributor cap that also squeaks time to time, it's also not the belt in which it would also make a squeal noise @ times and occasionally even work it's self of the pullies completely , but since replacement of new water pump,idler and tensioner pulley it seems fine besides now suddenly the screeching noise , mainly the noise happens with or when, fast and/or hard acceleration or revving the engine quickly, I also noticed now as well the oild pressure has been seemingly acting funny as I just recently even changed oild and filter however after the change and @ 165,000 miles I had right on 40lbs of oil pressure (according to the factory guage) upon start up & when cold and even once warmed up it stayed @ 40lbs ALWAYS and would climb to 40lbs immediately upon start up , but now suddenly it's started to take it's good old time climbing to between 30lbs and then some days 35 lbs and then today it was like 42lbs oil pressure but I personally believe it may be a bearing or piston issue or such but figured I'd ask for opinions or so on , my 1st 4.0 liter has been a heap of JEEP={Just Empty Every Pocket } 😂😆 😢😭 lol help me lol