James, That 49 ft retic was a hoax. When biologists or national geographic(or who ever it was that checked it out) got out there, the snake measured just 23 feet or so. The locals who had it said " we do not know why the snake has shrunk".
The longest authenticated I've heard of was right about 33 feet.
I dont believe many of the old records on snake length- especially with anacondas. Everyone says they get over 30 feet, yet I dont know if I have ever seen an actual believable account of one over 20. Many old records were taken by measuring skins- very inaccurate.