OK so I got the oil filter and the plate that is under it off.. Good news is the oil galley plug is installed.. I found an issue though may not be what was causing problem.. First when I pulled the oil filter off no oil started dripping down and the filter was about half full .. odd .. its a WIX .. but then the definitely not good item.. I had painted the outside of block with epoxy paint including the area under this plate.. A piece of it had lifted off the block and so was like a flap sticking up under this plate (blockage).. Its removed and rest is ok.. I've put the plate back on .. I've looked on forums and in my service manual and a few others but can't find the torque spec.. for the 1” double sided nut that screws into block to hold oil filter plate against block.. I had set my torque wrench to 40 ft lbs to take it off expecting to then work my way up to correct torque.. It came off before it hit 40 .. I have it set to 30 now but so far it hasn't clicked so may set it down to 20 then try 30 but I'd like to know what it should be .. the nut is 1" but the threads are same as oil filter but that is hand tighten and then 1/4.. Anyone know for sure what the spec is for that bolt? Thanks in advance.

Edit: Update .. I went and checked my receipts.. I got the standard volume standard pressure Melling M-72 pump for this rebuild

 

M-72 is good. I run the M-72HV and we put the high pressure spring in it.

I also dont see a spec for that double sided stud. I had mine off and put a billet Canton plate there (they did a batch for 25 of us back in 2019-2020); I think we just took it snug plus 10 pounds? Genuinely don't remember.

 

I was thinking of going to the 8 hole plates instead of stock one.. I just went to their site and noticed two things.
First they don't mention being able to use this plate on later Magnum engines but say fits "1967 - 1992" Mopar SB.
Second while the plate doesn't come with the double threaded nut they do provide this:
Note: Works with Mopar part # 53007563AB.
Torque to 30ft/lbs

So looks like 30 ft/lbs is good to go..
That is what I will use then.

 

Very subtle difference between the LA and Magnum, I don't recall the specifics. They did a 25 item pre-order in 2019 pre-covid that I got in on.

 

Sorry have not updated .. I have been waiting for new oil dipstick to compare to one that was in this engine.. Waited 2 weeks from one of big Mopar online sellers and was still sitting as 'in process' so cancelled it and now waiting from another seller.. Must be gremlins as this one sat in one depot for 2 days. Now its still sitting in another for 48 hrs while its only 30 min away... Arggh

I saw that the issue of oil dropping off when it hits up seems can be an issue with chevy SB. The o ring or the press on oil tube gets looser in pump and sucks air ? Since the Magnum 5.9 has a screw on pickup this shouldn't be an issue.. It does though act like all of a sudden when up to temp its occurring so maybe something in the pump isn't quite right.. I have the nice Felpro EverDry gasket. I have plenty of room under the pan.. I may drop the pan and verify the pickup is OK.. Also seems some say the Mellings aren't as well made as they used to be and should be spec'd before install.. I didn't do that.. I may get another and / or swap to a Mahle stock pump.. I'll probably get a new gasket just in case but try reusing the one that is in first .

 

Nothing is made as well as it used to be..... Manufacturers may try and convince you that their 'made in china' parts are 'just as good' as those that used to be made here, but, that is a line of crap. Chinese manufacturing simply is nowhere near the quality we used to get with parts made here. I only see that getting worse, not better.....

 

I think its important to share even when it was my own stupid mistake that creates an issue .. this to help prevent others from doing likewise so that said:BINGO! or should I say I'm a stupid sh#t .. I painted inside and outside of engine.. Well the inside paint let loose it seems Hot oil is a great solvent..

The bottom back of the pan and the entire bottom of the oil pickup tube was covered in it.. Screen on pickup tube was so bad .. I'm really surprised I had such great oil pressure until it heated up.. Lesson learned .. never paint inside of engine ..

It looks like its was only in pan around and on screen .. it didn't get circulated so hopefully guardian angle just laughing and no real damage done.

Stupid stupid stupid ..

I removed the oil pump to look at it closer.. Melling must have switched back from when I read reviews on their pumps as mine has Made in USA cast into it and casting is much smoother.. The oil pump showed no signs that the paint pieces got past the screen on the pickup tube. I reassembled and reused it.

In giving it a hard look over, luv all the room under this engine thanks to an offset diff, it appears what happened was the bottom edge of the piston skirts grabbed and popped off the paint.. The long stroke of the 408 gets them just to the edge of the cylinders. It in part was able to do that due to my not getting the block as free of any residues prior to painting it.. I didn't wipe down bottom of inside of block with solvents. The pieces of paint show how they had pulled off remaining contaminates.

There is only a few inches from bottom edge of cylinders to oil pan edge.. Thanks to access I was able to use a variety of scrapers, tips, etc to scrape or pop off any remaining areas of paint on block.. I will not know until its all back together and start it up but I am hopeful that since I was watching it carefully and shutting it down as soon as pressure dropped critical components were not damaged..I installed the oil pump back in making sure the hex drive engaged without binding and that the mating flange was fully seated before torquing it to 30 ft lbs.

I put a plastic sock on bottom of oil pickup tube then poured oil into pump itself so it was full of oil.. I was expecting oil to come out all over me once I was under vehicle and couldn't move fast enough LOL.. It all stayed in pump though.. I removed the sock so dumb dumb doesn't forget about it later today and put the oil pan on with it still covered. ..

Took a second for starter to catch again since I had to pull it to get oil pan off.. Fired up fairly quickly after that.Current oil pressure 70 psi but had that before.. real test will be when take it for a drive, it heats up, and the pressure relief valve opens..I carefully measured and added oil .. Five quarts (recommended) got me to half way mark on dipstick between add oil and safe.

Oil pressure was available immediately at just under 70 psi.. Drove down the hill to the resorts parking lot and did loops in it to get the temperature up.. was driving on slow side and kept fan off so didn't take too long.. Thermostat popped open and H20 temp gauge shot up to 190..

However this time the oil pressure didn't start dropping to zero .. sigh

Drove it back up hill to our lot and pressure dropped alittle while at the light waiting for it to go green .. I did notice that now unlike before the gauge seemed to move with rpm's .. Back up hill to our lot and still about 60.. Pulled into lot to park and as stopped to put in reverse pressure dopped but only a little .. the Scouts gauge was holding around the middle as well..

Not out of woods yet.. I did notice white smoke from under vehicle .. Not sure if oil pan gasket may be leaking or residual oil from removing or ?? Dipstick seems OK.

I'll let it sit for couple hours and see if it develops a stain under it..

.

I'm still in the break in phase with special oil.. If it seems ok I'll finish doing that.. When I dump that oil I'll pull the pan again and see what it looks like. I'll also watch the OP like a hawk until that time.

Oh and oil is showing up on dipstick when turn engine off.. The dipstick slides inside a channel welded inside the pan to get it to the back of it.. I'm thinking the crap stuck in the bottom was keeping the dipstick from seeing the oil until it sat long enough for it to make its way to it..

I still need to do more and longer test drives but it seems to be solved .. will add a follow up 'confirmed' in the future.
Thanks for all assistance, thoughts, and insights

 

Oil pressure will vary with engine RPM, and also engine temp. That's normal.

Relief valve is working as soon as you start the motor. The pump can put out some seriously stupid pressure, far more than the oil filter is rated for...... I had a Honda quite some time ago, that the relief valve jammed, so the filter was seeing the full pressure the pump was capable of putting out.....At startup, the filter would instantly become spherical, and then pop a seam. Very messy.

Some smoke after working on it is also normal. That's just stuff burning off from someones greasy paws bein' in there.

 

Glad you found the issue. Yea...definitely never paint inside an engine.

with 20-50 oil in mine, and the high pressure spring in the high volume pump, I get 70psi cold start idle and ~20-25 pound hot running idle.

 

Thanks for everyones help, insight, and thoughts.
This is final follow up on this ..
Just a confirmation after a 5 mile road test and a 15 mile power cycling run (on street dyno LOL)..
Everything appears to be running fine and oil pressure functions normally with it rising and falling as it should and holding PSI that is normal for temp and rpm it is at.
Remainder of oil (greasy hands ? lol) seems to have burned off with no further smoking occurring..
Dipstick reads as should and appears to be no leaks / loss of oil.
Thanks again ... safe journey to all.