I got my JMB intake,3.4 pulley,catless down pipe 180 stat,belt 104 plugs,ready to send PCM in for reprogramming.according to wbody site this is cool,but his email said no you will have knock with 3.4 pulley.? Will a power log eliminate this knock ? Or should I just keep factory stat and swap for 3.5 . Is the problem only with the front cylinders exhausting efficiently causing knock and piston damage for them to make half a header system ? If $ weren't a part of the equation it would be simple and get the plog. I guess the question is how much will I really be gaining / loosing between 3.4/3.5 and is it worth it . What would you do ? Trade 104's for 605's ? Thanks.