big block cooling issues

[SparkyRnD]

a new engine will run hotter than a broken in engine, so that will have some effect, but not a ton. You need to step up the fans to a larger size (also make sure you are using a relay system and getting full power to them). A good functioning stock water pump should work fine as long as your radiator and fans are up to the task. Higher volume does mean faster flow, but can lead to cavitation depending on impeller design and other factors. If you can keep cool while driving, but overheat when idling, then your fans aren't pulling enough air over the radiator. If you overheat while driving, then either you have a restriction or the shroud is blocking airflow