As said above, start checking pork butts around 195* F. The internal temperature can very from different pieces of meat. I use my Thermapen to poke the meat in several locations until it slides in with very little resistance. Sometimes that is around 200, or times at 205 or more.
I have never cooked ribs to an internal temperature so I don't know the answer there. I use a modified 3-2-1 method.
Smoke at 250* for 3 hours, wrap in foil for 1 1/2 hours, and sauce for about an hour. Sometimes they are failing off the bone trying to get them off the grill.