I scrape all that green goo and foam out of that area and fill it with glass or epoxy with 404 filler. You want the front of the pump shoe to be 1/8" protruding below the surface of the hull. At the rear of the pump, it should be 3-1/2" to 3-5/8" when measuring from the very tip of the stock 650 pump cone to the surfce of the stock FX pump cavity just below it. Search my original pump thread, I think I have pics there for ref. These measurements will establish the correct driveline angles. When you get it really close, you can mix up some resin (epoxy or poly) and wet the area and then cover with a piece of wax paper and set the pump in place and veriify you r meaurements...then let it setup. You'll end up with perfect mounts with no sanding/grinding.