I am also dealing with my ls2 swap running a bit hot. The fan shroud makes a big difference in cooling capability as others have mentioned so hopefully that helps. Are you running a stock induction system? I noticed my intake air and underhood temps just keep rising when I am not moving which also contributes to the coolant temp rising over time. The hood gets too hot to touch. Just make sure you have a good seal to the fender to prevent sucking in hot air into the intake.
For reference on other gm applications the cooling e fans don't even go into high mode until 235 degrees f and the overheat light doesn't set until over 250 degrees. So if you are running in the 220 range it might not even be considered "overheating" by design.
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