how do I tell which 3.5 engine is in my 2007 impala LT on 2007 Chevrolet Impala

need to know the difference between the flex fuel and regular engine

Asked by for the 2007 Chevrolet Impala
2 answers
Owners manual, information and emissions labels under hood, badges on car body or call dealer with/google vin #, yellow gas cap, sticker inside the fuel door for a couple more ways to tell. Look around you will find it! If you do not find any of these giveaway's, it aint FF!!
Contact me with the VIN and I will be able to tell you.