I personally preferr the E85 setup. This will allow you to run E85 with boost if you want to and still have the pcm pick that up. The stock pump on the E85 vehicles commonly are big enough to flow all of the fuel you're going to need for a boosted 5.3L. A TVS1900 on that engine would be bad ***. As for using the stock injectors under boost, even the 38's on the E85 engine aren't really big enough for much boost on a good running 5.3L and a returnless fuel system. On an E85 truck I'd go to 60's or bigger.

 

So if he bought the 5.3 with an E85 then if he wants to add an SC and run on gas...the E85 injectors and fuel pump wouldnt have to be changed?

what is the size of the gas injectors and E85 injectors for comparison?

Isnt the entire fuel system SS on the E85 or is it the same on both?

 

My Tahoe is a flex fuel but found a low mileage LY5 can I use the LY5 and just put all my components and wiring harness on this engine and it work
thanks