i installed a ported rt magnum cylinder head on my 2000 dodge neon. now its seems like i lost high end rpm's. why??

 

is your cam timing correct?
if your cam is advanced by just ONE tooth you will loose all of your upper end power

 

i set timing today . it got alittle better. i still lost power above 6k rpms. why? do i need more fuel ?

its a ported it r/t neon head with crane cam (nitrous profile)
race performance pcm
head back full exhaust system
60mm tb
iceman intake
underdrive pulley

 

How many miles do you have on since you put the head on? Sometimes it can take a while for the pcm to get used to the new stuff. Are you sure you lost on the topend? Maybe you gained enough on the bottom end to make it seem like you lost top end. Do you have an adjustable cam gear? Might make a worth while investment so you can degree your cam.