318 Main Bearing replacement difference.

Newbomb Turk said
Not exactly. That groove in the bearing sends oil to the rods full time. A half groove bearing sends oil to the rods only half the time.

It has nothing to do with how much oil gets to the heads.

Run the bearings. You’ll be fine.

Thanks. That's what I thought, but just can't understand why it would be changed from the factory design. I might understand if I was shipped a full set of upper and lower grooved bearings, but it seems like this is only going to provide full time oiling to the # 1 cylinder connecting rod bearing as the corresponding hole in the crankshaft only feeds the # 1 rod bearing. It just seems odd to me to have some connecting rods oiled full time, and others half time.

I also understand that the later roller cam 318's had a full groove # 1 main bearing, but I literally just pulled out a #1 lower smooth bearing that has been in that engine for 49 years, so at least in mid 1974, Chrysler gave the #1 main bearing cap (lower bearing) a smooth, non-grooved bearing. Maybe I should have just ordered Clevite to see if they supply a grooved or smooth # 1 cap bearing in their set.