I have a 1994 520H which is repowered with a 22HP Predator. I started the swap in the summer of 2016 after buying the 520H with a seized engine in fall of 2015 for $25 on it's way to the scrap yard. The predator has a lower crankshaft location which I corrected by raising the engine approximately 1 7/16 inches. Using a $16 ebay adapter sleeve the original clutch is used. Top of the air cleaner almost touches the hood louvers. The upper bracket bolt holes for the PTO had to be reworked to bolt to the block in the necessary location. The hard starting disappeared when I went to a 420 CA battery. I drilled and tapped the upper oil channel to install the factory oil pressure switch which turns on the warning light and runs the hour meter. It has almost 40 hours now and continues to run great. I intend to connect the factory tach in the next phase when connecting the vacuum guage. Looking for a vacuum source that will not affect engine operation. It handles a 60 inch or 48 inch deck in Bermuda better than my 20 HP Onan. Power appears better than the 20 HP Onan and more fuel efficient than the 1991 which has been my main tractor for 17 years and has 734 hours. It is also easier to mow with as it has the improved later style steering. Also have a 1987 310-8 with 36 inch deck for close mowing. All have clevis hitches and Ag lug tires for plowing, disking, and blade work. Use synthetic 10W-30 motor oil in everything, change filters regularly and expect all these engines to last many years.