Finding oil leak?

[Supra-in-steamboat]

Just replaced valve cover gaskets. Used FelPros. At high rpm- usually over 20mph- I am getting a bit of smoke rising from the rear of the motor.(@#3,4-and 7-8) I tried to locate the source with a mirror for @30 minutes. Cannot see any leaks. No oil in bilge. Oil level normal. Pics I took showed no smoke sorry. The smoke smells like oil dropping onto the exhaust. Could I be mistaking a potential oil leak for an exhaust leak from the exhaust manifold? Or maybe valve cover gaskets need to be tighter? Any advice on finding the leak? Maybe use a black light?

[Supra-in-steamboat]

Sorry- UV light and dye?

[beast 496]

Did you use rubber gaskets or the old cork style? Either way they should seal good. Did you clean off all of the old oil from the manifolds? Could be residual oil. I can not remember are you running the 351 or 454?

[Supra-in-steamboat]

sorry 351. Good point about the old oil. I did clean all contact surfaces before putting the gaskets on. I still have the plugs in that i fogged the motor with- but they are not fouled. Boat runs great though.

[Supra-in-steamboat]

Found an awesome Ford guy in town. Will not post anymore stumpers. Sorry. FYI it was coming from the plugs and is gone. Thanks for the reply Al. I did go with the cork style. As easy as it was, I can swap them if the cork doesn't work out. Thanks again.
dp