So I'm wondering what, if anything, would need to be done if I were to replace a flex fuel motor with one that was built for gas only.

I've got a high milage 5.3 with the flex fuel option, and a mechanic friendl has a freshly built moto that he'd sell me for almost nothing. It came from a gas only truck, and was rebuilt to those specs.

I know I would lose the ability to use the e85 (I dont use it anyway, so that's not a concern to me), but i was curious if there was any reason why a gas only motor wouldn't work if i dropped it in?

Would this be a straight plug and play, or would my flex truck need reprogrammed, or other parts replaced to go this route?

I've seen a lot of discussions about converting a non- flex motor to one that is, but what about going the other direction?

 

the flex fuel differences are all in the fuel system. injectors, fuel lines, pump as ethanol would corrode metal in a build not designed for it.

 

As tech2 said it's all in the fuel system. Stainless lines and a alcohol sensor in the fuel line to measure how much ethanol is in the fuel so PCM knows how to fire the injectors.