What is the valve clearance on my car??

It was coming from the drivers side toward the firewall and of all places to drip, the oil was dripping all over my headers....

It was very embaressing, people were looking at me as if i was driving a piece of crap, i didn't realize how much smoke there was untill i stoped at a light!!
I fixed it though, when i put the cover back on the head the far end of the gasket got caught on something and it kinda folded it back so the very tip wasn't sealed at all, Thank god i bought rubber gaskets, lol....

Thanks for all the advice everyone!!!