This is my 1st boa...

[Evenstar]

Yes!

That is a low ambient temp IMO.

This time of year I would be looking at 80-82 ambient and the a night drop to 77. Hopefully you have a thermostat that controls both hot and cold sides.

89-91 on the warm side as well.

There are some boas that do better with cooler temps and some that don't.

Also we need a lot more info on the snake.

Age, species, male, female, what was the breeder keeping it in for a cage??

Lots of factors.

They are more active than royal pythons in most cases.

Spot on advice here. I agree. I will add that 55 gal is a lot for a baby. Clutter it up well and give him plenty of privacy. Boas ARE generally more active and more outgoing than BPs, but any baby can feel insecure. Give him plenty of time to adjust and leave him alone for awhile. You'll soon see a change in his mannerism once he feels safe and secure.

Edit: Just saw you other post and this is a 6 year old boa?? If so, pictures of his set up would help a LOT. I still say give him time to settle in. But at 6 years old, he could be just laid back enough that he's not as active. Usually the babies are all over the place, but the adults, not so much.