$200 rescue, Columbian red tail boa

This is a snake we rescued-I'm scared to death of it. We've had him for several months.
When we got him he was in the middle of a bad shed and had a respiratory infection. He's better now, but I still don't trust him.
How big do the males get?

My male is over 4yrs old and in the 7ft range.

males tend not get as large as females but they are variable and there are can always be exceptions. I have adult males that are anywhere between 4' and 7'

I'm terrified of big snakes-If he gets too big I'll have to find him a new home.
He IS pretty though.
Can respiratory infections cause neurological issues?

I have seen male Colombian boas over 9 ft in length.
With the current attitudes regarding feeding, such large males are less common....but still not unheard of. The last 9ft male I saw was reportedly fed only 1 prey item every two weeks since he was a baby - not sure I believe THAT part, but

His disposition might just win you over....and/or he could stay a very manageable size.

Re: the last question - I think it would be pretty rare for a respiratory infection to cause neurological issues. More likely causes would be high overly temperatures (trying to "treat" the RI), overdose of (or sensitivity to) certain antibiotics, or other disease processes.

ok. I noticed he doesn't stretch out very often any more-acts funny when he is being held too. I know that the guy who had him before we got him didn't know ANYTHING about snakes and he was pretty sick. Was worried it might have caused permanent damage to him. His personality changed too. He used to appear to like being held, but now he acts like he wants to bite anytime you put a hand in his cage.
That shed just flaked every time you even touched him. He stays in our basement-all our other snakes are upstairs.

I've never given him antibiotics.

Oh, he eats 2 adult f/t mice a week

For one, he's not 7', I don't think he's 5' if those pics are accurate and that's someone's hand in the second pic.

Secondly, if he had a resp infection, he needs to go to a vet, they don't get better just from temperatures, it may appear to be better, but they will resurface if they aren't treated properly.

Third, he needs to probably be eating a med rat every 3 weeks or so, he's passed mice long ago.

Thanks, Chris

He should be eating rats, but he doesn't like them. He's not big yet-you can still hold him with only 2 hands.
He's only about 3 feet right now. I am having one heck of a time finding any reptile vet that's not 4 hours or more away. It really sucks. I've heard so much conflicting evidence on respiratory infections it's hard to know what to beleive! I've been told that if there are no signs that there is no longer an infection (by a vet 4 hours away from me-I am not sure what the name of the practice was. found it online and didn't make note of the name) and I have been told that you HAVE to take to the vet for it. It's about equal for the number of times I have heard both sides.