[Jack Shaft]

Original Winfield red head,7 to 1 compression on 'hard' babbit. Babbit does not fail from compression it fails from torsional vibration of a stock crankshaft and improper timing. Any increase in compression reduces the engine tolerance for improper timing, I prefer running a mechanical advance distributor for consistent proper timing at all speeds. To combat torsional vibration I use a murray horn harmonic balancer and have a mitchell OD to keep the rpm down.

Herm Kohnke felt the torsional vibration would push the center main journal .001 off center at 2400 rpm. Counterbalancing helps. Folks hear about racing upgrades like cross drilling the crankshaft and fully pressurizing the engine and invest big money into doing it,not necessary for a street car..Fords stock system works fine,the hydrodynamic principle (crankshaft floating on a film of oil) maintained by gravity in the A engine is capable of sustained high rpm (2400)..