Of course all this is just speculation, and the real answer will be known upon examination.
You lost a bit of compression in just the last 2,000 miles. Oil consumption has gone up significantly. Pressurizing the cylinders with air and listening for air leaks can help. Sound from intake- intake valve not sealing, sound from exhaust- exhaust valve not sealing, from the case- rings not sealing. Worn valve guides can give off blue smoke when letting off the gas at higher rpm as engine braking sucks oil past the guides. If you could get a hold of an inspection camera, you could pull a spark plug and check for scored cylinders.
You say there are 20,000 mi on your build. Can you tell us some details? Top and bottom end, just top end, parts replaced? How many blade fan are you using? The 2.7's tend to run a little hot. Did you install a fender cooler? What exhaust system?
I'm not sure, but I think the original 2.7 cylinders may have been Alusil, which do not take well to new rings. Also, you mention running rich, which can wash away the oil film and score the pistons and cylinders.
Oil smell can be oil from the triangle of death, or leaky valve covers dripping on the exhaust.
Walt, my '73 2.4 runs happily at 135psi with over 120,000mi. My '86 3.2 has over 180psi after top end rebuild and 2,000mi break in. Both have mild original cams, and a performance cam with more overlap and such may have lower pressure from a compression test, but high dynamic pressure in the upper rpm range.
As for the rockers leaking, I installed the RSR seals in my 3.2 when rebuilt, and used a slightly higher torque. If your rocker shafts were not removed in the last build, they are probably fine. If they were removed there is a chance they might have loosened, but I can't see that causing you to lose a quart every 500 miles.