After using the vaccum on it, and its all clean and free of dirt and stuff, take the tape back off the runners and wipe the gunked up areas out. Try your best not to let anything fall down into the runners. Once you wipe most of the gunk out, go to a local Dodge dealer, and buy a can or Mopar Upper Chamber Cleaner. Comes in a can with a white and blue label. Spray each runner down with the cleaner and let it sit, dont need to fill the entire area up, but make sure most of the inside of the runner and chamber are wet looking. This will help break up some more of that gunk off and let it burn out when you start the car. I did the same thing when I had to pull that head off and it helped. Also check that LS6 intake and make sure its cleaned on the inside, you can use that same cleaner to break up the oil and gunk in there, then wash it out, but make sure you let the intake dry well and its free of any water before putting it back on the car.