advancing cam advice

just bought a 350 chevy that i actually built last year from my sisters boyfriend we put alot of good parts in it. i didnt like his cam choice but to each his own. he went with melling 300 adv. dur. 488 lift I told him that was a mid to upper rpm cam but you cant tell young kids nothing. I'll be putting it in my 84 z28 he could'nt understand why the motor didnt pull good under 2500rpm then about 2800 it was like hitting the button. anyway I'm thinking about advancing the cam 2 to 4 degrees to lower the rpm range but have never did this before. would it make a noticeable difference or should I just change cams. like I said I built this engine last year.All new parts .030 over 4 bolt . 76cc heads (factory heads) we put 2.02 ' 1.6 valves manley swirl polished undercut and ported. I am however changing heads to my3873370 over the counter 300hp 64 cc double humps but Im going to port and install 202 valves. I will be running about 2100 stall . this will be a street car with ocassional strip any advice on the cam advancing would be helpful