i had the head milled down and how it vibrates bad do i need to put on another head gaskey or somthing to get that out it had 165 PSI of compression heres its mods

milled head NOT SURE HOW MUCH
DG pipe half silencer
no airbox just a K&N
uni airbox vents in the snorkel
and its just been rebuilt
and its ported

what main should i stick in it?