There are reasons why the 20-820 is a better/best filter imo, thus why when they were having stock issues 3 or 4 of us stocked up on them. For the guys running the 20-500, they have reported no difference in psi, it matters how much is behind the holes and the 20-500 is plenty deep, as opposed to the 10-48 that has more restriction. I'm not sure there is any value on anti drainback valve due to the location on a 1500, those help a little more when they are installed sideways on an engine, but I do believe there is one.
The beauty of the 20-500 is that loose thick media that separates rp from the field, and it has more then the 20-820. Fram Ultra is a close second imo, but those 20-500's have always been built this way, the fram ultra changes and hasnt maintained it's media identity for hardly any length of time. I have even had heat cycles in my wifes suv stiffen the media when there was a RP right next to it and it's media was fine. how can that be? Thanks to my wife, her car is a canister type filter so the media is what you see first, or we wouldnt even know this information, nobody cuts open new filters that were stored hot. It is a whole lot of information that you need to consider beyond just holes or an anti drainback valve where no anti drainback valve is needed in our application.. Operating psi and that beautiful loose thick media is the gem.
Valid questions g-ride for sure, and the title of the thread spells it out, your choices will be a big < =20-820. We thought puro boss might be a contender, the last posted test shows it is only moderately better then wix that is appropriately called the rock catcher. IMO there really are only two choices on filters right now that have been explored, RP and Fram Ultra. In both fairly scientific tests they both were on top, and it also jives with every test the forum has done on cutting open filters and research everyone has done. There may be other options out there, this market is contantly evolving, but from what I see there are limited choices, and why I was so worried I spent two hundred bucks in 2017 so I wouldnt have to worry about my ram. I literally had my truck tick on puro synthetic filter I still have a second one I might use as a flush sometime, but it was junk.
IMO it is a bit sad, if you want a paper filter you have a million choices, but if you want the best you can construct there is so few choices. Another option is to consider the blended filters, which fram ultra seams to be in and out of. It had to be blended media that caused my wifes filter to stiffen, spun microglass doesnt stiffen. Now, they "say" it is 100% synthetic, but they said that back then too. More fram ultra filters need to be cut open after intervals to verify, it is "possible" it can even be a better choice then out 20-820, but I have yet to see that evidence YET.
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. I would however stay away from those "USED" ones that are being offered on Amazon 
