oil in throttle body

Hey all my buddy just installed a Holley Systemax II intake on his 87 LX. When you turn the car off there will be oil coming oit of the TB. Anyone ever have this problem? Not sure where it is coming from to get into the TB or if this is normal? Only other mods to engine is a b cam and longtubes and 75mm throttlebody. Could pcv be hooked up wrong or is something else wrong? Any help would be great.

Yes he has the breather tube connected. It is not a little oil, when he turns the car off and open the throttle there will be a puddle in there and some will flow out of the TB. We noticed it when he installed the new intake and left the cai pipe off.