stronger valve-springs, need help

[Benjamin]

Hi guys,

i installed stronger valve-springs (help spings inside of the main springs in fact). i tooked the head of for this and installed a new headgasket.

now the car realy turn bad, the cambelt is good timed but the car is making much metal-noice, alltough i am pretty sure the timing isnt to advanced (early) :s
the engine also need more feul, but i wonder the springs can take so much power... i think i need about 300rpm more to have a nice idle.

is this normal, who else has installed stronger valve-springs.

Greetz, Benjamin