Hey Parkboy,
It won't hurt anything. I have them on 2 steel deck F engine mowers just like yours. Just take your blade retaining bolt off and slip the mulch fan on. It will fit. It goes under your blade, closest to the ground. The only thing is, I can't tell any difference when I have them on or not. Go ahead and give it a try. Maybe you
will have better luck with them than me. Good luck.
Jerry