Lack of oil

I'm looking for an oil pump that can keep good pressure at 6,000 rpm. My 383 has roughly 5,000 miles on it. A very rough and abusive 5,000 miles. I've noticed that every once in a while the gauge will drop to 40 psi when I get to 6,000 rpm. That is on the factory gauge and an autometer mechanical gauge. When I built the engine I installed a Melling high volume oil pump and kept all oil clearances for the mains and rods at factory specs. Every time I have the engine out of the car I always pulled the pan off and checked the bearings. They have looked pretty good until now. The bearings closer to the front of the engine are not getting the oil that they should be. As you can tell from the picture. This was the worst bearing in the engine. So now i'm trying to find a new pump that will keep up. This engine has always seen most of its life at higher rpms but I need to take care of this problem before it hurts the crank or worst. So far it hasn't done any damage to the engine but i'm sure if I don't get this taken care of there will be problems. Any ideas? Part numbers? Suggestions? This is the first small block chevy that i've really had this kind of oiling problem with.http://i654.photobucket.com/albums/u...7-18-09006.jpg

I'm running a canton oil pan for those about to ask.
http://i654.photobucket.com/albums/u...7-18-09003.jpg

One of the primary reasons GM changed the oiling system to Priority Main is my thinking.

I'm also convinced that the factory clearances are too tight. If or when I rebuild mine I'm going with .0025 of the rods and mains (but .003 on #5.)

The fronts are the worse offenders since they're the last to get fed.

I've read that opening the main oil feed holes in the block and in the main bearings helps.. Open, Chamfer and smooth the oil feed hole in the #5 main cap and, if niot already done, cross drilling the crank provides more constant oil flow to the main bearings.

You can find more info by searching using Google.

Jake

West Point ROCKS!

Ok crank has already been chamfered so i'm good on that. Heres a another question. What if I opened up the oil clearance more on all the mains and rods? What do you think .0035 to .004 would do? Well now that I think about it, that may not be any help at all. Melling has a new pump out that increases the gear size 25%. They are 25% longer. So it's more volume so that would help out with a looser oil clearance correct?

Why not opt for a high pressure pump instead of the high volume..

or high pressure and high volume

I've tried the high pressure first. I then swapped it out for the high volume high pressure. What kind of pumps (besides dry sumps) are guys using in autocross events?

Are you saying the high pressure pump still dropped at 6000rpms?

If so.. I'd be wondering about the placement of your pickup tube

Yeah high pressure dropped too. I am using a canton bolt on pickup tube that I have checked for clearance. I've got it set at 3/16" I am running 6.5 quarts of oil with this pan. Is there the possibility that it could still be trying to suck all of the oil out? I wouldn't think so.

Unless you have some kind of blockage it really sounds like you might be sucking the pan dry but I'm certainly no expert on the topic.

But aren't the canton pans (I have one) 7qt pans plus the amount the oil filter takes?

I think your right. I think it is 7. I kept thinking 6.5 for some reason. This last time I changed the oil I used a Moroso racing oil filter. Didn't cure anything. I've also tried K&N and an AC Delco