In a large skillet, cook 6 bacon strips over medium heat until crisp. Remove to paper towels; drain, reserving 3 tablespoons drippings. Crumble bacon and set aside. In drippings, saute onion, celery and carrot until crisp-tender. Remove from heat; stir in bread crumbs, parsley, garlic powder, pepper and bacon. Let stand until liquid is absorbed.
Preheat oven to 325°. Cut a lengthwise slit down the center of roast to within 1/2 in. of bottom. Open roast so it lies flat; cover with plastic wrap. Flatten to 1-in. thickness. Remove plastic; spread stuffing over meat to within 1 in. of edges. Close roast and tie at 1-in. intervals with kitchen string.
Place on a rack in a shallow roasting pan. Cut remaining bacon strips in half; arrange over top of roast. Bake, uncovered, 1-1/2 to 2 hours or until meat reached desired doneness (for medium-rare, a thermometer should read 135°; medium, 140°; medium-well, 145°). Let stand 10 minutes before slicing.