While I'm in there replacing the AC compressor, is there by chance a higher performance version to look at? The mega cab needs a lot of AC to stay cool, perhaps a higher capacity/performance compressor would help?

 

Here's a free bump for ya. I would be interested in this also.

 

I don't think so, but you can help it along a lot by adding three ball valves in an H pattern to stop the flow of hot water. The air path sends the warm air over the heater, then over the evap. Your taking 100 degree air, heating it to 190 then cooling it to 50.

 

You could also try a different refrigerant than the R134A junk they put in at the factory.

Duracool Refrigerant

This stuff got my van another 3° cooler outlet temp and is environmentally friendly! Just read the specs its good stuff.