slow throttle response

Have my (1st) Shelby 500 for about 6500 miles ( car now has 43K) on it. The most outstanding thing that I am UNhappy about is the UNDERwhelming throttle response. (Background) 1- Had Dyno’d after I bought it used. Factory rating of 540hp was right on with 3 runs @ RWHP 466,466,455 hp and...