From what I understand, the seals should be OK, if it's got a recent carburetor rebuild kit with new gaskets in it. A remanufactured fuel pump should work with ethanol. My theory is that if it works with the 10% ethanol you buy at the gas pump it should work with 85%. It will probably stir up some of the accumulated gunk in the gas tank, so a good cleaning is in order before use.

I'm not that familiar with the 460's, so I cant help much there. My interests are mostly in the FE's. So if you wanted to build that 390, stop by the FE forum.

Where to buy the fuel? Check here:

http://www.e85fuel.com/database/search.php

Power will be significantly more than gasoline. This comes from the fact that as it vaporizes, it cools the air and results in a denser air charge going into the cylinder. Also, if you increase the compression ratio of the motor, you get more power there too.