LB7 valve cover removal

[Pacific's Duramax E3]

Are there any special tricks to remove the upper valve covers on an LB7?
Tried prying on the tabs on the bottom and it won't budge and the seal isn't wide enough to be able to cut loose with a knife blade. Any suggestions or comments from personal experience appreciated.

[Kennedy]

Some times you have to pry to a point where you think it's going to break. Then just like magic it pops. A long solid bar with a firm and safe fulcrum near the tip is about simplest.