My engine (250 bored .60 over, 390 CFM Holley, Langdon's split manifold) otherwise stock, was rebuilt, now has 689 miles on it. I have a oil leak from the bottom of the timing chain cover, but it appears to be dripping down from the top. What possibilities to fix without pulling the cover.

first off 250 is gear driven No chain. But my question is If your seeing oil at the top of the cover Are you sure it is comming from there and Not Your Valve cover?? WHERE are you seeing the Oil come from first you said Bottom?? Then you say dripping from the top??

Twisted
Ther is no visible oil leak from the valve cover, or from the top of the timing gear cover. It is dripping from the bottom of the timing gear cover.

It could be any one of several things:

1. The seal was not replaced

2. The hub of the damper is scored enough that the seal won't hold back the oil

3. The outer metal ring was not sealed into the timing cover or one of them is distorted

4. The timing cover does not center the seal on the hub of the balancer

5. The bolt holes in the timing cover are dimpled to the point they prevent a good seal against the face of the block

6. The front pan gasket that seals with the bottom of the timing cover is leaking

7. The front lip of the oil pan is not making good contact with the front seal because it is badly pitted or distorted

8. All the bolts simply need to be gone over with a wrench and torqued back to specs.

One are i have seen a small issue with the sealing is at the edge of the timing cover and the Oil Pan Rail. where all the gaskets lap each other.

Twisted and Mike.
There was an issue with the oil pan rail and the timing cover, but that is resolved. I will look at these other possibilities over the weekend.
Thanks for your responses.

Rick C.