I believe there are two seperate records currently being held. One is the "Longest" Currently held by a Retic at over 32' and the "Largest" Currently held by the Anaconda at over 300Ibs.
Just something to make you think though.
Just imagine a Burm, Rock, Retic, Anaconda Ect. living out in the Farout forest, Somewhere that is 100% Untouchable by Humans. Do to no Human contact this area would have all the food that a snake could possibly want. I have seen some Unbelievable Burms, Rocks and Retics in Captivity at or above 20' living in Roomsize Cages and still considered Young animals under 10-20yrs. of age. Now look at the Snake in the wild on top of the Food chain in the deep forest where no man has ever seen eating everything it wants and living to be upwards of 40yrs. old. IMO. The Potential of there being snakes in the wild that reach or excede 40-50-60' is not to far off track. So far there has been several "Undocumented" sightings of Giants in the wild. There has been Several people that after venturing off into the forest where never seen or heard from again. Just think of the potential of one of these animals in a locality like this and it Makes you realize that The Movies "Anaconda" and "Python" are not all that far from the truth. 
Just my .02cents worth that is prob. not worth that 
Take care
Justin