Hot Rods Oil in Downpipe (SBC)

I'm redoing the exhaust on my SBC, but only got as far as putting on the DPs. I started it once after redoing the manifolds, and then it sat a couple of weeks with just the DPs on. a few weeks later I found a small puddle of oil under the passenger side DP, and the inside of that DP is amberish oil Sludge.

Where is this leak coming from?

 

Down pipe meaning exhaust collector? Pull plugs or just that side , see if oil present,, could be bad valve seal & guild , You did not say it smoked , could be
Stuck ring / Broken, warn.
(( leak down test or compression test))
Or leaking Valve cover leaking oil on to exhaust manifold gasket ,then running in then out threw down collector

 

Yeah, I meant exhaust collector/manifold. (I'm relatively new to this generation of cars, have mainly worked on 2000 era VWs, so some of my terminology needs to change.). I put on the manifold, and the first pipe before the muffler, and noticed the oil coming from the exhaust pipe

That's another point I forgot to add.. I inherited this car as it is, and the exhaust was in horrible shape and leaking badly, so I never really let it run for extended periods of times cause of the leaking. So I never really noticed smoking, but I did notice the drivers side was spitting out what I first thought was soot, but now believe to be oil... (The passenger side looked fine for the most part) So I pulled the entire exhaust off and am in the process of putting a new one on. Before I did that, I noticed the leak after the passenger manifold... So I guess it looks like both sides have issues.

I'll check the plugs and see what's up.

 

All so possibly sucking oil at the intake to head on one or more of the
runners / ports , by pulling the plugs witch identify "if" witch cylinder to check (oil) ,
May be check intake bolts for loose , not tight enough

 

Don't know but with oil dripping out of the exhaust, I would think you would complain about the smoke. Just a guess but could this drip be just water? condensation? With the short "down pipes" maybe not but ....