I have just rebuilt a 350 engine for my truck. The bottom end was done at a machine shop. Heads,push rods, roller rocker arms, intake, valve covers were installed by myself.

the problem I'm having is when I turn the engine on to break it in, theres a loud banging/knocking noise coming from the engine. It's more then a loose or sticky rocker arm ticking. The noise does increase as rpm goes up. I checked the PSI (compression) on it and the #2 cylinder has about 175 to 180psi compared to all others at a 150psi. Also the header tube on the #1 cylinder is cold when all others are warm/hot.When checking all the plugs they all have signs of ignition.

I'm not sure what it could be right now, either a bend push rod or maybe the rocker arms could be hitting the valve cover's which are aluminum so it might make a louder noise but it definatly sounds like metal on metal contact somewhere. Any help or ideas would be great!!!So far no other forum knows

 

Quadruple check your firing order.
Use a timing light on your cold cylinder to see if it's firing.

Ignore the plugs. If it's firing out of order it's still firing and won't show you much of a difference between it and the others.
I pulled a duh before and swapped 2 plug wires. Had a dead miss that I didn't even feel until the converter would lock up. Talk about a vibration.

 

Took me a while but through trial and error i got it. I forgot to mention that the truck used to be a one piece rear main, and is now a two piece. With that comes the larger end on the crank and the bugger was bashing off of my tranny inspection cover. As for the compression issue i readjusted the rockers and that seemed to even everything out. Also after close inspection of the dist cap the no1 prong was lose. Luckily it's 2 days old and i switched it under warranty. Thanks alot for the suggestions though.