N6571R crashed into trees near the VOR on top on Hinch Mtn at about 3000 feet MSL. Trees at the crash site indicated wings level with a descent angle of about 10 degrees. Weather in the area was IMC, characterized by low ceilings (lower than the mtn top elevation), rain and fog. The pilot had refueled at Livingston, TN en route to Florida. The flight originated at Blufton, OH. The plt reported that the weather was getting unfavorable and he made a 180 degree turn. He also reported, after the accident, that he had experienced a power loss and was unable to restore power. A treelimb with 2 propeller slashes indicated substantial engine RPM at tree contact. The plt purchased the airplane 4 mos before the acdt and replaced the engine with a remanufactured engine in Nov 87. His family said he had flown the airplane about 7 hours afterward, before this flt. The plt held a private pilot certificate and was not instrument rated. The pilot had not filed a flt plan and there was no record of radio contacts drg the flt.