Sense everyone seems to be a keyboard engineer. Let me throw something out to think of.

When you put fluid under pressure what does it do? When you force fluid by a releif valve what does it do? Just something to think about. I have come to realize on my Caterpillar backhoe just starting it up and letting the fluid pump for a few minutes on a cold day the fluid well warm up considerably just because it is going through a pressure relief valve. So I start paying attention to other things like automatic transmissions. A chrysler tranny does not pump in park. You can run it for a day in park and the fluid will not warm up. Put it in neutral and the fluid warms up.

So you run a high volume oil pump and do not have the clearance or passage to use the oil so it goes through the pressure releif and warms the oil. This is why belt driven pumps are popular so you can slow them down and adjust the releif.

Now to the full groove question. Half groove works fine. I doubt seriously anyone reading this thread has ever made enough power to need the extra surface area considering how large the mains are on mopar cranks. I know personally I ran full groove P bearings for years with heavy doses of nitrous along with bad tuneups and never muchroomed a bearing. Chattered main caps from detonation but never hurt a bearing due to having a full groove taking up surface area. Just something to consider.

Leon