WHILE CRUISING AT 10,500 FT WITH THE POWER SET AT 28 INCHES MAP & 2350 RPM, THE ENG SUDDENLY LOST PWR & BEGAN KNOCKING. THE PLT NOTED A RAPID DROP IN OIL PRESSURE & SAW A 3-INCH HOLE IN THE TOP OF THE ENG COWLING. HE ATTEMPTED TO LAND ON A HIGHWAY, BUT WAS UNABLE DUE TO VEHICULAR TRAFFIC, SO HE CHANGED HIS APCH TO LAND BESIDE THE ROADWAY. JUST BFR LANDING, HE SAW POWERLINES & PULLED UP TO AVOID A COLLISION. THE ACFT THEN ENTERED A HIGH SINK RATE (STALLED). THE PILOT STATED THE ACFT 'IMPACTED THE GROUND IN A FLAT, RATHER NOSE LOW ATTITUDE.' THE ACFT BEGAN BURNING IMMEDIATELY AFTER IMPACT, BUT THE PLT EXITED THE PLANE WITHOUT INJURY. A TEARDOWN OF THE ENG REVEALED A CATASTROPHIC FAILURE OF THE #2 PISTON AND WRIST PIN, BUT THE INVESTIGATION DID NOT DETERMINE WHICH HAD FAILED 1ST. THE ENGINE HAD BEEN OVERHAULED ON 6/5/84, USINGSEVERAL COMPONENTS (INCLUDING PISTONS & PISTON PINS) MANUFACTURED BY SUPERIOR AIR PARTS, INC. ACCORDING TO MAINTENANCE LOGS, THE ACFT HAD FLOWN 1045 HRS SINCE MAJOR OVERHAUL OF THE ENG.