Whenever I have to work around my AC compressor, I just undo the bracket and try to move it out of the way. The hoses allow for some reasonable movement of the AC parts. That way I don't have to vacate the gas. But I have a van, so I don't know the flexibility of your truck AC lines.

 

 

Can you disconnect the engine mounts and move the engine to gain more room? I once saved an almost new but out of warranty Ford engine just by replacing two of the pushrods. The engine was a crate replacement and sat for long periods of time. The shop that installed the engine several years earlier said the engine was toast and offered another replacement. So the owner parked it. After a compression test, I removed the valve cover to find two bent pushrods, one each on two cylinders. The crate pushrods were heco en Mexico and half the weight of the replacements from the local dealer. Replacining the two pushrods solved the problem.

 

Smart move with the engine mounts. I did that to replace the heads on my van with the IDI still in the engine bay.

 

 

Keep in mind I made a prognosis over the internet (insert Dr boogie here). If they were all stressed/torqued up I might say yes as they were adding sheer to the rocker arms. I thought it sounded like a dry rocker arm on the spring retainer or as if the surfaces were gauled and the valve stem was worn/damaged and ready to drop.
Those rods must be replaced and at about $14 each is a good starting point. While you are at big a autozone/ advance, pick up a stethoscope for about $25. The stethoscope will practically pinpoint other noises like roller bearings, etc. Rod and mains take a little learning as rods are quick repetitive and mains are slower. Wrist pins- typically stiff, make a similar noise to rods but the noise is not as deep into the block.

I did not hear the knock noise you are referring to, but a sticking injector would make a similar noise and a stethoscope will find that quickly.
With the stethoscope you will be working toward the noise, hold it firmly against the surface (keeps noises true and produces less static that will damage your hearing) and be careful around moving parts.

 

Somehow I missed this. You can check the straightness of the pushrods by looking at it or by bringing that valve to a closed position and loosening the rockerarm enough to turn the rod. If the pushrods is bent you will see the curve as it is rotated and the rocker arm may move side to side. Best bet is to remove them and check for wear on the ends, rockers, stems, retainers, and stem-hieght/keeper to spring retainer.
Rocker arms should put pressure on/contact the valve stem and not the spring retainer.

 

 

Did you check both sides?

 

 

If your rocker arms are touching the springs you have some serious problems. Either the springs are a larger diameter than appropriate or you're referring to contact with the retainers. If that is the case any rocker showing that wear is very far gone, and the valve likely is trashed as well.

 

The rocker should touch the tip of the valve stem and NOT touch the spring retainer. Touching the retainer will likely cause the keepers and the valve stem to wear and eventually the engine will eat the valve. You need to check your clearances. Maybe rockers are worn, or retainers and keepers are damaged. I'd suspect this is your real squeak noise since these surfaces are not machined and polished to permit smooth movement and prohibit wear.