you wont hear the knock. its in the cylenders (to much hot air in the cylenders and the spark plug is igniting when its not supposed to, spark knock) go back and check out the kr stickey (knock retard) there is scanners you can buy to read how much or if any that your getting. you are almost gaurenteed to get some with that pulley and stock exhaust manifold (cant get the hot air out)

i would highly suggest headers and a way to get it scaned. also look into a tune.