Will this radiator work with both engine sizes, or do I need different cores?

This single radiator is rated for both 3.6L and 5.7L engines — no need to buy two. Cooling capacity is matched to the larger engine, so either one runs comfortably within its design window.

Does this come with a new thermostat or bypass hose?

The radiator assembly is sold as a core; thermostat and hoses are not included. You'll want to grab a fresh thermostat and new hoses while you're in there — standard maintenance during a radiator swap.

What prep work is needed before installation?

Drain the coolant system completely, then disconnect the upper and lower hoses at the radiator. The radiator lifts straight out at factory mounting points — no cutting or welding. Reverse the process to install, refill, and bleed air from the system per your service manual.