bigger fuel system??

any help you guys got would be greatly appreciated. i just got done putting some more mods on my gt. stock heads got a five angle valve job and milled .030. i removed smog pump, installed an electric fan, comp cams shaft (new lifters, springs, and still got stock pushrods) cant think of what duration is but the lift for the cam is .512 int and exh. and i installed trick flow 1.7 rockers and put on a TF track heat upper and lower intake with a 3/8 in. spacer. along with my other mods is it time to upgrade to bigger injectors, fuel pump, and grab an adjustable FPR? The reason i ask is cuz the engine revs fine from idle up until about 4500 then it starts fluttering like its not gettin enough of something??? i changed plugs and checked wires that helped but didnt get rid of the problem
 
if you dont have one, a FP gauge is gonna be a friend now. see what pressure you got at higher revs. good luck.