Sorry this is so long.
Put a std pump in my eng. D&D recommended a high volume pump, my eng builder and TA Performance recommended against it. Reason being don’t need it. The oil pump drive from the dist is a weak point and the high volume pump puts more stress on it. That being said I wish I had more hot oil idle pressure, while off idle no complaints. Also “tuned” with the bypass spring. If I was to use a high volume pump I would definitely go to a 10/30 rather than a 10/40.
Currently running Pengrade 1 10/40, Will be trying 10/30 VR1 and see what pressure looks like. Better flow, better oil.
Whether you go with the high volume pump kit or a STD rebuild kit from Melling get a “booster plate shim kit” from TAPerformace. It is a series of shims from .001-.009” that allow you to shim the thrust plate the gears run “against” to the optimum clearance.optimum clearance = optimum pressure. They also have a kit they call a booster kit that has a steel plate that goes in between the gears and the orig end plate that ensures a perfect surface and the ability to set the clearance just right. Pay attention to the instructions that come with the kit. Neither kit costs much. Also sell the Melling rebuild kits as do lots of people.
They also have the correct gasket for the bottom plate, whether you use their kits or not. The gasket I got with the Melling kit did not have a relief that our pumps need. I believe it’s for the 3.8 V6 that uses the same pump. Either punch out a hole or get a proper gasket as per the picture in the Factory Shop Manual shows you. Otherwise the pump will blow out the hole for you and launch paper into the system somewhere.
Finally, if you like research, read the blog. Ratblog540. It’s a great, long article on oils, filters. He discusses how oil performs, ZDDP, how different weights and different types perform. He rates oils with hard data and explanations to support his ratings. Gotta scroll around a bit but oil ratings are a little ways down from top and oil filter discussion and ratings toward the end. AND he will respond to questions, takes about a day for him to do so. You will see your question and his response in the blog.