I rebuilt my 38" deck on my Cub Cadet #72. That baffle, It's Not a guide, was rusted bad and bent up. I cut a strip of steel about twice as thick and made it tall enough it hangs just lower than the tips of all three mower blades. I used a short piece of angle iron, about 1" per side and 1/8" thk to reinforce the points where the radiuses meet. And I arc welded them 100% to the underside of the deck. Performance of the mower deck improved a great deal. Yes, the paint on the top side of the deck burned off but rotary wire brush it and repaint it which I'm sure it needs anyhow. The discharge performance of the deck improved greatly. I also put a lip under the front edge of the front of the deck to form a bit of a tunnel cut grass clippings can flow through on the way to the discharge chute. I also cut the top of the left end of the deck, end away from the discharge chute so it has a smooth radius all the way around from the back wall of the deck, and around the end and blends smoothly into the front wall. Those changes and the new bigger stronger baffle increased the distance my deck tosses clippings at least 50% more than stock. With the clippings getting out of the deck quicker it pulls easier and mows much more evenly. But it still doesn't perform anywhere close to the 54" deck on my Cub Cadet Zero turn, it has big baffles side to side plus the longer blades run faster and throw clippings about NINE FEET from the end of the deck! I've never seen it leave a windrow out of the discharge chute like the old IH decks did. Most clippings land 4 feet to 9 feet away from the mower deck.
On the 38" deck I did weld right angle impellers to the angled wings about 3/4" high, they run within 1/4" from the underside of the deck housing. I REALLY needed the increased airflow and to give the clippings a REAL PUSH out of the deck when running my home-made lawn vacuum. Moving all that additional air it pulled harder but it would suck stray leaves up to a FOOT away from the deck under the sides of the deck housing. And the hot-rodded 14 hp Kohler pulls it fine. The old 10HP struggled to just run the mower deck.
I don't vacuum the yard anymore, the lack of clippings & leaves requires yearly fertilizer applications. SON did field test a new prototype stand-up lawn sprayer/fertilizer spreader his employer built, it even had foam markers for the spray boom and LCD read-outs for spray volume and fertilizer application.
