Are these body proportions realistic on a guy?

The neck is too wide besides that it's fine. :)

It's pretty good, to be honest. I suggest that tu make a grid as a guideline(3 por 3, squares). tu draw the head in the middle and the shoulders should fill up the squares on the left and right. What tu did is quite all right, but I think the shoulders should be a bit más broad. Other than that I think it's OK.
Tips on how to make the torso look better and más defined: link