I didn't weigh him, obviously, but you have to consider that he was up to 245 at the end of his career when they wanted to make him a hybrid FB/HB/short yardage back. He was big, though. If someone saw him on the street and didn't know the face, they'd have thought he was just a regular dude.
Whoever added that to his wiki article got it wrong. For example, a August 30, 2006 article said this: Davis has been frustrated at the length of time the injury has kept him out, saying, "It's getting to the point where it's just draining me. I'm tired of watching. I've been here and I've worked hard with everybody else and I can't be out there and help. It's just killing me watching." (LINK) Domanick's third season in the NFL was cut short by a knee injury that caused him to get surgery to repair the lateral meniscus cartilage in his left knee. The Texans and their medical staff thought Domanick would be able to make a come-back for 2006, which is why they passed on Reggie Bush and took Mario Williams. However Domanick's knee injury turned out to be more serious that they thought, and they put him on IR for 2006. It was a big deal at the time, being that the Texans had just passed on Reggie Bush. Domanick's knee kept bothering him the whole 2006 season, constant swelling, etc. At the end of the 2006 season, Domanick underwent another round of knee surgery, and the Texans cut him to find a more healthy running back that didn't cost them as much money (he had a $22 million contract). Domanick became a free agent, and nobody wanted to sign him because of his bad knee. But he was a big star before his knee went out.
I used to date his cousin from Breaux Bridge. She said he's about as big as Breaux Bridge now...and rarely has a day where his knees don't bother him...
Domanick Davis' cousin is on the LSU team -- John Williams, the 4-star ATH/CB we have that is currently running the GA Tech option offense for the Scout team as QB. Both Domanick Davis and John Williams played high school ball for Breaux Bridge. Like LSU, Breaux Bridge's mascot is the Fighting Tigers. Since 2000, three other Breaux Bridge players came to LSU: DE Charles Alexander, DB Jesse Daniels, and DB Jonathon Zenon. For those that don't know, Breaux Bridge is that town on I-10, about 10 miles east of Lafayette.
I highly doubt he's anywhere close to 350. The guys is only 5'9" and weighed 215 while with the Texans.
Thankfully he did get a nice contract before the serious injuries set in. I'm sure there was a sizable signing bonus.