Sources for pre-09 5.7 long blocks / cores?
I also like the idea of going to a factory intake as my oil change setup absolutely sucks. The ModMan has next to no provisions for it, just a 1/4" NPT threaded port that's meant more as a breather than a fill port. I think Indy wanted you to buy their valve covers with it and use the port they put in those (at least I thought they put a port in them, maybe not). The other issue is the lack of PCV.
I've also wondered if my oil eating issues are PCV based as I had a fair amount of oil in the intake when I took it off to notch it for my A/C compressor and noticed all the oil on the back of the valves. It's possible my engine might be healthier than I think (like maybe I can save it with just some fresh bearings), but it's hard to say. I took a total shot in the dark on a PCV valve for a similar sized engine and just kind of hoped for the best. I originally tried to run a homemade catch can, but I don't think I did it very well and it was completely full of oil when I removed it. Now I just have the PCV plumbed straight to the throttle body base like a stock engine. I'd prefer to have the real factory setup to know for sure it was working correctly. That would also get me o-ring intake ports instead of the gaskets that I'm running now, which might also be leaking vacuum into the intake. There isn't a ton of clamp on the intake with only 1 M5 bolt or whatever size it is per port. With a plastic intake and o-rings I think that's probably fine, but with a cast aluminum intake and gaskets I'm less impressed.
It's kind of tempting to see if I could send the ModMan somewhere to have grooves cut to use the stock o-rings...
Just some things to think about below. I have no skin in it, just maybe helping with some ideas that don't lead you directly from "it's used some oil" to "I need a new engine"
How Hemi and LS guys didn't suck their oil pans dry with the PCV-Less intakes, and cheap, non-orificed, fabricated valve covers, is beyond me. (not sure what valve covers you have, and thats not directed at you)
Your consumption issues could 100% be because you just have a vent plumbed right into the throttle body. In testing, we ran some Hemi's and LS's without a PCV restriction, and had to even finely tune the orifice size of the PCV barbs, to balance between building pressure, and suckling oil. I have personally see a Hemi and LS drink enough oil with no PCV, to where it wouldn't have went an oil change interval. The LS drank something like 1.75 quarts in 1000 miles without a PCV restriction/orifice.
Have you bore-scoped the cylinders? done a compression test, or leak down? you might be lucky enough that all your problems are PCV related.
I have 4 late model hemi vehicles. Here's the mileage
252,000
128,000
112,000
38,000
Never been inside the longblock of any of them.
The 252K mile Jeep gets oil changes every 5000 miles or so. it uses MAYBE a quart in that interval.
Hemi's can also push oil past the coil packs, on the spark plug tubes, and oil pressure sensors are also notorious for leaking past the plug. something else to look at.
hope all that helps.