My suggestion is do the basic engine detective work to find out why the pushrods are bent. Was the engine like this when you bought the truck, or did it happen afterwards? Did the cam jump time because of worn gears / chain? Did you lose compression in any cylinders? Are the rocker arms all galled up from a lack of oil? Did someone install a high lift cam and not make sure the springs have proper clearance at full opening?

There are way too many possibilities of the cause without more information.