how to take off the head off my sr.. and a smal lil problem

[Id RaThEr DrIfT]

okay i wanna take off the walve cover/head to see what kinda cams my car has and to see what's broken cause just recently my car was leaking oil from the line to the turbo so i wasn't using my car, i decided to use my car yesterday without boosting, since i knew it had leaked a lot of oil but i had to pass up a bike to get off the freeway and ever since then my car CLACKS everytime i rev it/ give it gas and its comming from the head ... i already fixed the lines that were leaking and put oil in but now i wanna see what it might be. my dad said it might be a lifter or a rockerarm stopper what u do u guys think? and how to take off the valve cover?

i took off all the studs/bolts except one cause its just spins but doesnt come off but anyways the cover doesnt wanna come off. is there a specific tool or way? THANX and any help would be appreciated .........