motor is a B18B... Thinking about picking up some main studs due to the power that Im making on a 100% stock engine. My question is, can I just pull the valve cover & remove my OE head bolts and replace them with the studs WITHOUT pulling the entire head off? I realize that I may need to remove the cams...

 

You can but it's not recomended ndont be lazy pull the head off and do the gasket

 

You should pull the head and replace the head gasket at the same time you're installing the head studs for sure.

 

I have gotten away with it many times installing the head bolts without removing the cylinder head. The gasket bond has been created and it is almost better to not disturb it.

Let the engine cool completly, remove the coolant, remove one head bolt at a time following reverse torque sequence and install the studs.

I have done both d-series and b-series engines this way.

 

You can totally remove the head bolts and replace them with head studs without taking the head off but I wouldn't advise doing such. You've half way to changing a head gasket, might as well go the full distance and change it. Also, I'd change the timing belt as well while everything is a part.