I am currently 6'4" and about 176 pound. Last year when I started BJJ I was a soft 185. After about 4 months, I was down to a skin and bones 167. I just couldn't keep the weight on. Plus, after a hard working, I would feel tired and sore for 2-3 days.
It su#@*ks being in ur 40s.
wow, ur really lean (i mean that in a really good way). doing kung fu, i want a really lean build. not only does it help with speed, quickness, conditioning, but it is also easier on the joints.
how often do u train? my schedule is so hectic i dont get to attend as many classes as i want. i take two classes on the weekend for kung fu. i also do 2 cardio kickboxing classes during the week at a place near my home as well. i also started tkd, so i go to one class a week for that.
i do about an hour of kung fu training every evening at home, but as much practice as you do, it never matches an actual class.
im in my mid 30s and they kind suck 
I have a pretty tight schedule. Normally, I get 2-3 classes and 1 personal training in a week. Plus, I lift weights twice a week at home after the kids go to bed.
The classes I attend are at lunch time. Luckily, my job is pretty flexible like that. I really wish I could train more, but life with a full-time job, young kids, and ample time on CB doesn't leave much time for anything else.
It seems that you are getting in a good amount of training. You just need to find an hour or two a week to add in some ground fighting/BJJ

I have always been fascinated with Kung Fu, but have never trained. I understand there are forms, but do u also do breaking? What type of sparring do you do?
I was in China two years ago and was able to catch a televised fight on TV. It was between two guy in full ceremonial-style Kung Fu garb on a game show like stage. It was full contact with no gear. One fighter was in his 50s and the other was maybe 25. It reminded me a bit of Muay Thai as there was no ground fighting, but there were kick/trip style take-downs. It was pretty brutal. The older guy won, but they were both pretty beaten up.
Mk