I can see that you have limited experience.
Boas are much different than balls.
They are much much more outgoing and "curious" if you will. Their feed response is ten fold that of a ball. Food aggression is not uncommon with boas.
My 7' girls will eat your face for a rat.
As far as a 55 gallon, if it is in fact a 55 (48"x12") That is indeed enough room, but you may have a hard time getting your temps right.