Lot of the spark plug designs are driven by the EPA standard that an engine has to run and no produce excessive emissions for 100,000 miles, so they have to last a really long time. The other thing to consider is what type of ignition system the vehicle has and the design of the plugs to work with that style ignition. The more energy it takes to Ionize the gap at the plug the more stress there is on the ignition coil. One reason why most modern engines have one coil per cylinder. I have seen lots of ignition coils burnt and replaced when the root cause of the problem was a spark plug worn out.
You may have, and not know it, problems with the spark plug wires, coil wire, and not the plugs
I have had them wear out on one of my old bracket motors using the MSD 7 and 7AL2 race boxes, the carbon coating on the plug wires center conductor at the distributor cap burns off and will start missing a tiny bit in high gear about the 1000 clocks in the 1/4 mile
. Cut the ends off and reterminate them and your good to go for some more racing
