I hate to ask something like this because it's probably been asked so many times before but I couldn't find anythign on a search . What are the best plugs to run in a 98 year engine ? I 've been over on the RegalGS forum since I now own one of those and have read a lot about the best plugs for the s/c 3800 which turn out to be regular old copper core plugs for a stock motor . So what about for my LS1 ? Right now there are AC Rapid fires in there and it seems to run fine . I'm planning on getting some indexing washers soon too . Any suggestions on where to get them ? Thanks