Largest colubrid in the world - not North America - right?
Spilotes and Ptyas Carinatus can get to up to 14' in length.
Weight wise - well, awhile ago on another forum, someone stated that it was the FWC.
At the time, I scoffed, until I saw and held what I could only describe as a full grown "bull" male FWC.
It had to be close to 9' or more in length and was heavier and girthier than any indigo or cribo I've been around.