This may sound dumb, but have you checked to see if you don't have the fireing order on your distributer reversed? Reason I say that is me and a friend of mine got my rebuilt 455 back from the shop and the mechanic said the distributer rotated reverse of a chevy, so we set up the plug wires that way. When we couldn't get anything, we took the cap off the distrib and guess what? It rotates the same way as chevy.
