digginfool Start with the basics, make sure the ign system is ok
Swap plugs first to other bank and road test, see if problem is in the same side of the motor, if yes
Swap spark plug wires to other side and retest. I would install new cap and rotor. What make of cap and rotor are you running?? Have had alot of trouble with MSD cap and rotors over the years. Only takes a couple hundred miles to kill the center contact terminal in the cap and it still looks ok. if problem still there
Compression test
Leakdown test these 2 will give you a good indication about the motor's soundness.
Now to the tuffer stuff
Pull the valve cover on the bad side and have some one crank the motor
check for a full range of motion on the rockers. Make sure you have the right valve lash. You didn't say if the motor was a solid lifter one. Check and do the lash on the whole side. If the popping is still going on, I would be looking at lifters if they are hydros or sticking valve or out of round seat in the head. You will get good compression and the leakdown test will not show a problem. This is because the valve spins when the motor is running and hits the sealing parts more times than the bad spot. Been there, Had this happen.
Does the
oil smell like gas?? or have a funny feeling to like?
Use a sparkplug socket with a rubber insert. This will stop chances of cracking the plug. Also if you use anti seize, it is possible that the heat range of the plug can drop 1-2 ranges because of the paste on the threads. Rick L.