more bad news
Did that set of rockers come straight from Cam Effects or from TGSI? The reason I ask is that you need a few more parts to put it on you car.
At a minimum you need whatever was decised upon to make the top of your lifters flat for the roller to roll across to make it work. If you want to install a valve cover as well, you'll need a "shim" of sorts to go between the valve cover and the head to give clearance for all that purple goodness.
You could just give up on them and send the parts to me. After all your car runs the way it is, this has been so much trouple and all, I didn't get in on the group buy in time, and you realy don't want to try to get the valve cover over the stud girdle in a GT. I'd even go so far as to take your partial kit off your hands for, say, 70% of what you paid for it. See it's that easy to get rid of the hassles associated with those roller rockers.