Stuck valve

Hi, i have the truck listed above flare-side with a 5.7 TBI v8. the truck sat for three years. i did spark plugs, cap, rotor, coil, wires, a new/used throttle body, fuel filter, and even vacuum lines. the truck ran good for a bit until it bent a push rod and i figured out that it was a stuck valve. i got it free and made sure every valve was moving and then put the valve covers back on and it ran it sounded more beast then ever. so i let it sit to warm up then go check the timing it ran for about ten minutes and sounded like it was popping a very tiny bit and all of a sudden the engine stopped. it gets close to firing but just likes to shoot a six foot flame through the TBI. i have tried moving spark plug wires one over and even adjusting the distributor but still no luck! please help me.