head swap question

Put your socket on the balancer bolt and rotate the engine around so the pair you're working on have both valves closed when you're installing the rockers - that is, so the lifters are on the base circle of the cam for the valve you're tightening. That's the proper way to do it. Yes it's normal for the rocker to open the valve when you tighten it if the lifter's on the lobe of the cam. Now, if all of the valve springs are being compressed - whether the lifter's on the lobe or the base circle - then you've got some valvetrain geometry issues - probably pushrods that are way too long.

its most likely that the lifter is sitting on the lobe of the cam.. turn the motor and see if it goes down