Oil usage insanity, help me find the source! (pics inside)
 

So I finally finished my engine build several months back and put it in. It runs amazingly other than the fact that it's leaked 4 quarts of oil in the past 1100 miles or so. Engine has about 1400 miles total.

So, with this kind of oil usage, I should be leaving a slick on my garage floor larger than this, right?

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And that spot seems to be dripping from the bottom of the tranny, see all the fresh looking oil in this pic?

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And this:

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So this leaves me with 2 conclusions:
1. My rear main or rear oil pan gasket are leaking and most of the oil is staying in the bellhousing while only letting a tiny bit escape through the weep hole.
2. I have some mystery leak from the back of the head

Here is evidence supporting the leak from the back of the head. If you look closely, you can see a channel of caked oil running down the bellhousing:

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Now, i've checked around the back of the head as much as I can visually and by feeling, but i'm not finding any fresh oil anywhere. Not from the CAS, not from the VC gasket.

Another note, my spark plugs aren't oily so I dont think there is a problem with valve seals. Something I haven't checked is the Cam seals although I dont see how those could leak to the bottom of the tranny and if they did, I see no trail of oil leading between the two points. I will check them once i've eliminated the external leak possibilities.

I'm waiting on my real mazda PCV valve replacement still, the one in there now seems to be a piece of shit. Doesn't act like a valve, can blow through it from both ends. Maybe i'm crazy or retarded.

On a separate note, these allen head plugs around the head should be replaced by the machine shop when they rebuild the head, no? When I started this engine for the first time this plug was missing and I didn't notice it. All the others were in there, but this one shot 60psi of fresh oil all over my driveway. Pulled a plug off the old engine to fix it.

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No matter where the problem is, this is the last time i'll ever use felpro gaskets. I say this every time I try to use them but i mean it this time. I fought them hard on my Integra and finally went with acura parts and no issues since (they are cheaper too!)

So, ideas?

attach some sponges with mechanics wire at different spots on the engine. Wait a couple days and then remove the sponges to see which ones have oil on them.