Like the others ave said...cut into smaller pieces and cook hotter. I usually get the pork butts from Sams and cut as best as possible into halves. Cook like 300-325 and wrap when the outside looks like you want it to. Don't cook so much to a specific temp but more to feel. When they're probing nicely....when you can slide in and out easily a probe....they're done.
Proud owner of 4 VERY ugly drum smokers....and a Greasy Hill reverse flow....