chevy 5.3L

[banabana]

I found a 07 chevy 1500 4x4 5.3 that only uses gas, no flex fuel. Is that a completely different motor than the flex fuel 5.3. One of my friends has a 09 1500 5.3 that runs flex fuel and regular gas does that have the same hp and torque as the late 07 models with the new body style that run only regular gas? From what I've read online the flex fuel model is the L59 and the regular gas is the LM7, is this correct. And I've heard only the gas-E85 5.3's switch into 4 cylinder mode to save gas which means there more efficient than the gas only 5.3's, is this true. Basically is there anything bad about a 07 chevy 5.3 new body style that doesn't run E85? Is it less powerful, worse mpg, slower? thanks

[Badass69]

The flex fuel engine basically just has larger injectors to accomodate the difference in the stoich ratio between gas and E85. Obviously the tuning is different but that is just the PCM......Otherwise for all intents, the engine is identical. So no, either or is fine.

I am assuming you are talking about the GMT900 chassis though, as Active fuel management never existed in the GMT800's. Personally stay away from the early AFM 5.3's, the things are junk. The lifters GM used ( and quite franky still use) do nothing but cause more problems than they are worth. If you don't believe me just type in AFM 5.3 into Google and see what it gets you.