If you are running a 42" mulching deck keep the original 4blade set up. If a 52" side discharge you can purchase the mulching kit option (works very well) if you have the 54" or 62" your kinda out of luck mabey gator blades. for-warning 52"deck is nice its belt driven if you hit something the belts slip, if you got the 54" and you hit something you will break the shear pins off or worse take out the gearbox. Talk too your local Walker dealer. We sold of our 54" decks and replaced them with 52" mulch kit.
Dont get me wrong with the other decks im not bashing them we had a couple of problems with them.