[tubman]

Ya' know, after thinking this over, the "N" series Champions (or equivalent) may just be the correct plugs for these. Add and extra plug washer, and everything should fall into place, eliminating the need for spacers, etc. Don't really know if it's the optimum solution, but that's the first thing I'll try when I use these heads. I do know I want all of the threads engaged that I can with aluminum heads.