The Pontiac 347 was a great endurance engine. I saw them give 150,000 trouble free miles of service when the proper oil change and tune-up intervals were observed. There is a '57 Pontiac Chieftan two door post here that has the factory Tri-Power setup and it still is a very dependable and fast engine. The only changes I'm aware of is the change out to a HEI and some carburetor modifications. The 287, 316, 347, 370, 389, 400 and 421 were all excellent engines in my opinion.
Normbc9
