2001 Chevy Suburban Fuel pump trouble

I have changed the fuel pump 4 times and it needs changing again. The first times I concluded it was due to a dirty tank since I found out the third time the mechanic was not cleaning the tank when he replaced the pump. The fourth time it was changed I saw it my self be cleaned and they also found the power line to be faulty like three inches before the plug to the pump. The mechanic said that could have been the cause or the very extremely dirty tank. I cant decide which one caused those pumps to burn out. But this time I had the wires looked at and pump changed and it still burned out. Usually I would hear the pump make a noise like before but this time nothing. I was also wondering if I change the pump for it with a 5.7litre instead of a 5.3litre would it affect in any way fuel economy or performance in a 'bad' way?(The last question was just extra knowledge for me)