95 SC vs. 95 Z28

well my brother just got a 95 Z28 6 speed a few weeks ago and i had just finished putting on my 3 inch exhaust so we were out crusing down I70 and we went from a roll at around 75 and i stayed pretty even with him all the way to the top of 3rd when he let off. and i raced him a few times from around 2500 in 2nd (in my car) and we stay even till i hit 3rd and he starts to pull but only gets about a car on me. he has 3 inch magnaflow catback and a cone filter and i have K&n filter 5% pulley and downtubes to magnaflow resanator to straight 3 inch.