the one you took out was 4000 or the one you just put in it was 4000/ also do you know what the 1/4 mph of the old set up was? sorry to keep asking about the rods but you have not said yet? well my buddy was so posed to look and see what my rpm was though the 1/4 mile last year but he kept forgetting to look at the tac.lol oh what kind of brakes does the your car have on it? also my best time so far through the 1/8 mile has been 6.70 at 101.90 but i have not done any tuning on the car yet. man if you put a set of eddy aluminum or a set of indy EZ heads like i got that car would fly for sure. but i think its running damn good for what you have right now.