89b2200
+1y
Those intake and exhaust lash adjustment gap specs are for mechanical lifters. The hydraulic lifters are not adjustable. They get noisy when the hydraulic lash adjusters get dirty and the ball check valve gets stuck not allowing oil to pressurize them and remove the lash.
Sometimes, adding 1 quart of ATF to motor oil will clean the lifters due to high detergent additives in ATF. Drive it until the next oil change. If the ATF trick does not work, you have to pull the rocker assembly and shafts to get those HLAs out for cleaning. You can do this with the motor in the truck.
Once you get them out, try to squeeze them. If you can squeeze them, it is not getting filled with oil due to a stuck ball check valve inside the top hole.
You can try cleaning them by squeezing one in between your thumb and index finger while pushing the ball check valve through the hole with a paper clip or a pin and immersing in a cleaning solvent. Do this a few times until you can see solvent getting sucked in and squirted out when you compress it while pushing the ball check valve with a pin.
If unsuccessful, it is stucjk and may need replacing. They can be expensive like $25 a piece or $200 for 8 pieces.