Small oil leak on left side of cylinder head
 

I just did my head gaskets and I have a small oil leak that only happens when I'm running at freeway speeds and comt to a stop it then drips on the exhaust a stinks . If I don't drive it above 45mph for a long time no leak. So I put some die in it and ran it for ten minutes on car rack and no leak . It must need more pressure . The leak looksmlike the head gasket is leaking oil right on the left side of block right where head gasket is. There is a squar part where the block sticks out and it drips from there. I did a smoke test and don't see any smoke. I thought it might be cumimng from back of intake and when I come to a stop moving forward a bit and driping.
I'm not sure .

Worped block? I did have the heads surfaced .
This sucks I hate the smell of burning oil !