So I pulled my 4.0 replaced the timing chains, oil pump, water pump & the passenger side head. I had to replace the head because it developed a crack and started sucking coolant. The truck has 215k miles on it so I decided to pull the engine and replace the head & timing chains.. It's a good thing I did because the timing chain guides were pretty much gone. This is where it gets weird. I get everything back together, I primed the oil through the engine by turning the ignition without the spark plug wires hooked up. I did this 20 times for about 5 seconds each time.. I then hooked up the spark plug wires and started the truck. The truck started right up but had a knock for about 60 to 90 seconds to be exact.. It knocked just long enough for me to walk around the truck then long enough to put my head under the front pumper to see where the noise was coming from. I wanted to see if the noise was in the top or bottom. To be honest I'm not sure, I kinda thought bottom end at first. It didn't do it long enough for me to really pin point it because as soon as I stood up it stopped. I've put about 100 miles on the truck since it stopped and everything seems to be normal. Nothing odd or out of the ordinary. No check engine lights or anything. My question is, is this something I should be concerned with? What would everyone else do if this happened to them? Any feedback would be greatly appreciated. Also, thanks for taking the time to read my story.