/6 overheating need help.

So you say you did all the mods a long time ago. Then that means it WAS running cool with all the added stuff. Is that what I am reading? Does it overheat on the road and cool off when you slow down? Does it overheat when you come to a stop? Any additional details will help. I agree though, the shroud is a very important part of the system. It should not have been left off. I would put it back on, even if it meant putting the original radiator back in. You said yourself it didn't overheat with the original radiator, so that may be an option.