Yes, it'll fit out the door. The photos may be a deceptive, but the stack is only about 39" long. It was that length when I pulled it out of the scrap bin and will need to be cut down about an inch to get the 38.194". Since its near the top of an already tall 275 gallon tank, I won't be worried about smoke blowing in my face from the chimney.
I'm by NO MEANS WHATSOEVER an expert but I wouldn't think you'd have to worry about cutting an inch off your stack to get the number from the calculator. Dave or one of the other experts would know for sure but I thought one of them said in my thread for my build that numbers don't have to be exact just pretty close to operate effectively. Just a thought.