For a truck application I really like P5153325AB.

It's smaller than a 6.1 cam but larger than a stock 5.7 cam, and it doesn't drop any off idle torque like 6.1 cams are prone to in 5.7s (granted that's easy to fix with gears, more converter, etc)

It's also only $211.00 retail, and is readily available...Chrysler has 11 of them in stock so any dealer should not have a problem getting it.