I think that ridge is there to help "hold" the gaskets in place while you're installing them, nothing more, as the clamping force of the four bolts will hold them in place once installed. Of course I could be wrong, but if you have a spare float bowl laying around (I may have one somewhere, I truly don't know), I think it would be an interesting test to grind/machine that ridge out and see what happens, as I've had this same problem with the 4150 in my truck.