Out with the old, in with the old.. for now

Alright, so that Craftsman II I was planning on building is no longer. Apparently it didn't feel like moving a car lol
SO, found a cheap enough 12.5HP Briggs Dynamark w/ no deck and not running, showed up and he got it started.
Brought it home, needed a carb clean, air in tires (popped one off bead just by moving it), and battery charge. Put it in the backyard for a day, and found another (MTD?) 12.5 HP 38" for same price, didnt run but same exact motor so figured it could be a good parts machine. Got there and engine is completely seized, no oil in case at all, but at least no holes blown in it either. So went to start Dyna and solenoid is shot. Perfect, grabbed it off MTD, threw it in, took the carb (better shape and newer) and threw it on, and after charging the batt., she started up great this morning. Drove it around for a few min and got off to listen and it sounded like it didn't have full power, kind of stuttering. So I hit the throttle linkage by hand 3 times and the 3rd, time, POOF, shut off and white smoke pouring out exhaust. I knew it had oil, but I guess I didn't check very well because it has twice as much as it should. Looking it up I've heard head gasket or oil breather is most likely the case, since it still has compression and turns over. Anyone agree/disagree? Have ideas? Thanks! It's getting cold out (first snow last night) so any help is appreciated before I go out there blind. Also, there was some oil in the carb/airfilter tube, looked close to breather tube entrance.

Sorry bout the pictures, not really sure why they're that big

Use the forums built in image uploader and make sure its set for Forum (800px width).