i rebuilt a chevy 350 motor. i put in a new cam, anti pumpp up lifters. 1.6 ratio rockers. and had the heads redone with all stainless valves and they were milled down. my car this year which is the same car as last year only with a fresh motor is slower than last year and last year i had stock heads, stock lifters stock rockers. the only other thing i did was advanced my cam 4 degrees to get my power a little quicker. please help