synthotic oil

Dad did the first oil change in his 78 power wagon 360 when it was new to mobil 1.
Changed the oil once a year since then.
At 213K the rear main was leaking and ruined the clutch.
We pulled the motor to change the clutch, dad said to rebuild the motor while it was out, I pulled a main and rod bearing it looked new. Just threw new gaskets in it and it still is running fine at over 240K.
Good oil and clean filter is the key to engine longitivity.