67 383 spark plugs/what ta use?

Bob,,,ya I understand you...I would want more as well if a Honda is giving me fits. It wont take much to improve that engine. The heads are the worst small regular valves and poor flow. A set of closed chamber heads would raise the compression and get it up and moving I would think. Nice car, I also have a 383-S automatic...tossed a 440 in it and tucked the 383 under the bench...just easier and now its fun, even put the original exhaust manifolds away for a set of Schumakers Tri-Y's 440 source heads, six pack pistons aluminum water pump and intake all painted factory engine color...nothing super fancy but its fun now :)
You mentioned a set of Closed Chamber Heads would perk up the 383, any details/suggestions? A friend of mine has smog motor 440 heads on his 383, and races w/pump fuel. I like that idea, but don't know if Smog 440 motor Heads are Closed Chamber..TBD. And, what to look for??