Oil leak rear top m617 ideas?

[ngarover]

Chasing an oil leak I seem to have at the rear top of my engine. Only seems to do it while driving (pressure) the engine is not creating any bad pressure (rings) and the oil cap is steady and does not dance around at all.

In the picture look at the bottom of the hood and you will see the oil spray, it also gets on the firewall below that area of course.

I thought it may be the valve cover gasket as it was old, so I replaced it but still happening.

Any ideas?