danc30 Dan looking at the plugs I see no coolant issues. There would be a chalky material on the plug or it would be cleaner than new. You have fire in all 8 cylinders. Which manifold are you running? There are some manifolds that have a 10-40 cfm differents in flow. Is this a single and dual plane. It's all about matching ports. IMO the center 4 cylinders are going to get more A/F than the outer 4 cylinders, 1,4,5,8. Did you call KCR and ask about the prssure problem with the coolant?? The problem I think is a pin hole or weak spot between the head gasket, 1 cylinder and a coolant passage. If you really want to equal out the cylinders and pick up a little HP, Joe Craine will balance the ports of your manifold. Takes about a week, looks like jewelery when you get it back, motor runs smoother. The other thing to get is an intrared temp gun for checking the heat temps on the exhaust manifold with the car running, EGT can vary 20-100f degrees and give you the same thing with different sparkplug colors. I am going with the fact the car doesn't blow black smoke out the sidepipes, no missing, no backfires, basic things. Does the 1 wet sparkplug smell like gas?? Are you using any antisieze on the spark plug threads? This will also cause problems with the sparkplugs not firing correctly. Get 5,000 miles on the motor then we will know after the breakin if the Jetting needs to be changed. Installing an A/F meter in both side pipes is the best tool for checking for Lean or Rich conditions of the motor at all RPMS. Lets find out about the preesure in the coolant system first than look at the other things.
Rick L. Ps Dan I am not a big fan of NGK plugs, Put a new set of Autolites in the motor and road test for 100 miles then pull them and lets see what they look like. Check the plug gaps.