No, this was built by a company who specializes in hemis.

I'm still waiting on the parts to perform any more tests. Everything is taking forever in shipping. It never blew the dipstick out, however, it was one of the flexible Milodon tubes and because of the multiple bends to get around the headers, it took a decent amount of effort to pull the dipstick out, so it would take a ton of pressure buildup in order to blow it out. I'm Not sure on what you mean by the breathers leaking. I didn't build the engine, so I'm not sure of any of the alignment specs with the crank out. There are no side seals installed, so it's not being pushed off center. The crank seal area appears ok visually. I'm believing that it is excess crank pressure due to the fact that it'll run for a few minutes and then start leaking a bunch of oil all of a sudden. If it was a sealing or alignment issue, theoretically it should leak all the time correct? I'm believing that the pressure is slowly building up and then it gets to the point where it has so much built up and the rear main seal is the weak point and it starts leaking there. It's just a theory at this point until I can perform the recommended tests.

Is something blocking the breathers from doing their job(something in the covers?)? I would think if this thing is building that kind of crankcase pressure it would be blowing vapors/oil out through those breathers. I've seen engines with poor ring seal AND a PCV system push oil/vapor out the fresh air side/breather(more blow-by than the PCV can handle). So I think an engine without a PCV and excess crank pressure would blow that all out the breathers long before it would push past the rear main(or any other seal)

I had a 4.3 GM come in years ago....it whistled out the rear main...lol...didn't really leak much, just whistled . Messed up PCV system. Fixed that and sent it on it's way, never put a seal in it. Just my

I have noticed vapor coming out of the breathers before

Major crank problems or.. do you wash down all the retainers and block with carb cleaner so there’s NO oil residue? Seals and sealants won’t stick if there’s any oil left on the parts. Are the seals installed in right direction? A little dab of black silicone in the corners is all that’s ever needed, never had a leak.
Another thing about the pvc, you CAN check how good it’s working by putting a vacuum gauge in the breather hole, if everything is sealed up tight it will show vacuum.

You are going to see a bit as ALL motors have blowby to one degree or another. That is exactly why the PCV system was mandated by the feds. How much you have is the question? That will be answered with the gauge. Any thing else at this point is wasted speculation IMO.
FYI: either 5/16 or 3/8 tubing will fit the d/s opening. You may have to reduce to o/d slightly with a file or belt sander. for a loose slip fit. You can put a short piece in with a small amount of RTV, allow it to set up, hook up your gauge with a piece of vacuum tubing and do your test. if you're going to drive it, make sure the tube is long enough to put the gauge on the windshield on inside the car

I finally got the dipstick tube installed and hooked up the pressure gauge to it. I ran the car for about 10 minutes, no leak, and the pressure gauge didn't show any pressure. I could see vapor coming out of both breathers but I guess they're venting enough not to have any pressure building up. I also ordered a pcv valve and I'm going to install one with a catch can as well.

If your test was done at idle or under no load conditions, the next test would be to run the gauge inside the car and drive it normally watching for pressure build up.
Then Romp on it hard in 1st, & maybe 2nd or 3rd while preferably having someone watch the gauge.
If it starts to build pressure you have inadequate venting or poor ring seal. What the gauge does under a load at WOT will give an indication of which.

if all is good, you should repeat the test after installing the PCV

Finally got the chance to take the car for a test drive. No leak from the rear main seal, but now it's dumping oil out of the front seal area.

Crank, pan, or timing cover. Be diligent in finding the actual source as it will move around up front.
Have you done the pressure test while driving ???

I believe it's the front crank seal, but I didn't get a chance to clean the engine up yet, the entire under side is covered in oil. I didn't have a hose long enough when I took it on a test drive, I'll try to grab one tomorrow to test it while driving. I don't know how it could even be building pressure at this point. I only drove it down the road maybe a mile or two and both breathers were open, I left the dipstick out of the tube and I left the oil fill cap off to vent any possible pressure that it could be building. It's not leaking from these areas either as they are dry.

Advance auto sells a Wearever brand (house brand) brake cleaner in an aerosol that is great at de-oiling things and has virtually no odor. I had it analyzed and buy it by the drum from a local solvent supplier but don't have the name of the solvent handy.

the solvent name would be greatly appreciated, especially from me.
TIA sir !

tetrachloroethylene and acetone

https://www.aapmsds.com/msds.aspx?id=072084b8-033b-4893-81c0-c5974819d2a4

I'll have to check my suppliers info to see if it is the same as I haven't bought the advance stuff in over 10 years. the stuff works great and has virtually NO ODOR.
I used to get it for .99 a can in case qty's but they jumped the price to 1.99. My wife through her work knew a local solvent supplier. They analyzed it tand I started buying it in 55 gal drums and using sure shot refillable sprayers. Cut the cost from .13 an ounce to about .03
And yes i'm a T/A and we used a lot of it so it was a significant cost savings

Update on the engine issues. I drove the car on three different occasions that were roughly about 10 miles each. Rear main seal is dry, however it is leaking from the front seal/ oil pan area. I installed one of the m/e Wagner adjustable pcv valves with an oil catch can in line to try and vent any extra pressure and create a slight vacuum inside the crankcase. The valve is setup for maximum flow in fixed orifice mode as per m/e Wagners recommendation on the phone. I ran the engine for about 5 to 10 minutes and the leak is still there and now my rear main seal leak is back. I'm still not showing any pressure on the gauge when it's hooked to the dipstick tube.