after oil pressure drop, now i have a knock

[Whtknight64646]

I just bought an '88 half-ton with a 318 5.2L. 3 days after i started driving it my oil pressure dropped to nothing on the gauge and the oil light came on. Now i know it wasn't the sending unit cause i did start to get a knock.

I have fixed the pressure problem.(cause by sludge build up) Now when i try to run the engine i get a knock. I have been told by several people it could be caused by a few different things. ONE-Main bairing and rod, TWO-lifters, THREE-the timing chain could be going out and slapping against the timing chain cover.

This knock that i have is not a constant steady knock and it is definetly effected by the RPM of the motor. When just idleing it becomes very speratick and somtimes hardly noticable, but when the engine is reved up it is definetly more pronounced.

I haven't been able to determine if the noise comes from the top bottom or front of the engine due to the fact that i dont have a stethescope to get a better ear to it (nor do i have more "oakie" means like a long screwdriver or broom handle).

I was wondering if anyone else has had this problem or if you know exactly what is wrong. I would also like a brief explanation on how to fix it.