my 350 blew up an I cnt decide between putting a 350 back in or changing over to a diesel. wht would be better the 350 or the 6.5L diesel and would I have to change out my 4L60E tranny if I turned it into a diesel

I'd imagine you would also have to change the fuel tank (nozzle size), fuel pump, electronics, possible front suspension parts with added engine weight, and plenty more if you converted to a diesel. Keep it with the 350. If you want a diesel, sell the k1500 and purchase a truck with a diesel already installed.

people who have 6.5'* take them out and put 350'* in. the 6.5 is unreliable and gutless. the tbi 350 is one of the most efficient and reliable truck engines gm made. if i was going to change it to something else it would be a 5.3