I feel ya.. china rail seeping oil is my bane so I use Right Stuff. Usually once you get one corner moving it'll release. Razer blade followed by a wire brush usually does a good cleanup. Ultra black will likely be fine as well.. just be sure to measure the gap and get a good size bead in there. If you don't see a bit squish out all the way around you likely did not use enough. After i dropped the manifold on I forced a bit more into the crack at the front as I did not get the amount of "squish" I wanted.
GL!:thumbsup: