Hello Tim
I have a replacement MOW 140/318 deck of 48" width that Jay speak's of. it came on my 1983 John Deere 318 when I bought it. It did not mow good it clumped up grass for me. I live in Knoxville, Tennessee where we commonly get a heavy dew each evening and our grass often does not dry out until very late in the afternoon so this clumping was Posing a problem for me. I looked at the blades and they were the Low lift blade's. I thought about buying the speed up pulley for my deck but it was over $75.00 for one, so I elected to try a set of High Lift blades.My John Deere Dealer told me that I could not run High Lift Blades on my deck I have No Earthly idea why he would have said that Perhaps' it is considered a Liability issue now as the High Lift blades will throw an object hit a lot Farther than a Low lift blade will ? I went with them any way & That did the trick for me the grass cut's much cleaner and bow's out fine now. I hope this helps, Kurt