351 dual sump Canton pan leaking so I pulled the engine

[PKRWUD]

Didn't we already go over this? If the gasket surface on the pan is straight, and the surfaces thoroughly cleaned, it won't leak. The only silicone you need is a small dab at the corners where the end of each seal meet the block. THAT'S IT! Any more silicone will cause problems.

The only other possibility is you have the wrong end seal (unlikely), or the pan isn't truly flush. To check it, clean it completely, get a flashlight, and a large piece of glass (a big picture works great). Turn on the flashlight, and set it in the middle of the glass, with the glass sitting flat on a table. Place the oil pan OVER the flashlight, and set it on the glass, in effect hiding the flashlight. Turn off the lights in the room. Walk around the table, looking at the point where the pan meets the glass. If the pan is bent at all, the light from the flashlight will show you where. Correct the imperfections until it's perfectly flat, and you're good to go.

Take care,
~Chris