just bought 68 Coronet RT 440 with 55,000 original miles. the sparkplugs were never changed. the sparkplug boots were permanently annealed to the sparkplug porcelin, had to cut them off. I noticed that although it is a HP block they have some kind of log manifold on it which is kind of big and prevents you from working on top on most plugs, in fact the three on the passenger side had to be gotten from the bottom and the front passenger side needed an 13/16" open end, nothing else would do, took 2hours and 20 minutes a god awful job. anybody done this and come up with better tools or procedure? I have 1000's of tools and the only thing that worked remotely was a small 3/8" ratchet with a 1" extension..I plan on pulling the heads soon to mill them and I am now thinking of attaching the correct 6 pack exhaust manifolds and sparkplugs before bolting on. any thoughts here people.