NelsonPerformance.com for a tune. Any radiator that fits your truck will cool the LSx based engine. Be sure you get good fans if you go electric. I would suggest the Black Magic fans since they pull more air than any other aftermarket ones I could find, come with an adjustable thermostat and seals against the radiator with a soft rubber seal to ensure air flow through the radiator. You can use the factory electric fans off of a Camaro/Firebird on a 28" radiator or 2005 Silverado fans on a 34" radiator. It all depends on how much room you have under the hood to fit a radiator.