oldaman

have two 455 manual/auto cranks # 397363 one looks normal. the other one has oil grooves on all main journals except the rear main. these grooves are machined into the journals 360 degrees connecting the oil holes they look factory . question is would this work for a street motor 90 percent cruising. or did somebody have this done for a race engine.all input appreciated

cutlassefi

67OAI

Most shops stopped machining fully grooved mains back in the 1960s-1970s. Was thought to be a performance oiling enhancement for race engines. Since Oldsmobile used fully grooved main bearings on their engines there would not be much reason to groove the mains on the crankshaft.

oldaman