Doghealer,
Your little one looks so much like Apollo did when he was a pup, the only difference is the ears. (I see the coon in them!
)
Apollo is 20 months (well, will be in 3 days, but hey, close enough!) and he weighs in at 140.5lbs. I have noticed that he slimmed down recently, but his legs are getting longer, so I think we're in the midst of a late growth spurt. (oh yeah!) I haven't measured his height lately, will have to do that tonight. The pic in my avatar was taken 3 months ago.
I would say that your pup shows every indication of topping the 140 mark, maybe even larger. Great advice was given, watch his feeding habits closely, weight should stay proporionate to his height.
Have fun watching him grow, and I hope to see oodles of pics!!!