Part number 5007420 is the latest most up to date part number. Your carb bowls can be removed and sanded flat by putting down a sheet of 600 grit sand paper on a flat surface and lap them in a figure eight pattern. Check them with a straight edge across two surfaces. Bowl warpage is usually from overtightnening the bowls after a carb rebuild. If you order from Ishop you will get the latest part number in the BRP system which is the 5007420. If your are going to order from them and want to save even more money order the 5007423 VRO which is the same VRO pump but is an upgrade kit for the old style 3 wire system. The VRO is a 4 wire but they give you a purple wire to add to the engine harness and a new 4 pin connector. Order 3 new carb float gaskets. If you have to order new bowls have some Nitro ready.