I just resolved some knocking on my engine, was due to over advanced timing. My old engine couldn't even take 12 degrees. I'd check that first, most common cause of knocking. However, you normally get knocking when the truck is under a slight load, or at high temperatures. If you only get it when your foot is completely off the gas, there's something else going on.

 

update, i think maybe i have one of the cams like a hair off or something, the only way to keep it running (running like crap) is to keep my foot in the gas about half way and when i have my buddy turn the distributor cap either way it bogs down even further. when the crank mark is at 0 that is for sure tdc? no way it could have been bottom dead center? today im going to take the timing cover off and try to get it dead on again.

 

Any chance your distributor is a tooth off?? Have u checked the timing with a timing light??

 

Just get yourself a $20 timing light from Harbor Freight and do it right. There's no way to tell what you're timing is at by just turning the distributor.

Jump terminals E1 and TE1 (like you're pulling codes), turn it on, let the truck warm up. Set your idle to 800ish RPMs.

Hook up your timing light and shine it down on the indicator (you might need to put paint in the tick mark on the pulley if it's hard to see). Set it to 10 degrees, that's the factory setting.

See page 25: http://personal.utulsa.edu/~nathan-b...e/64tuneup.pdf