Its the ELS 724 24hp Briggs they have in the bigger Craftsman mowers. They had issues with the air cleaner system allowing dirt to get past the filter and tearing up the cylinders,,, This was a warranty replacement a guy had on the floor... Runs great for now I put a pre filter in the housing to catch more dirt prior to the filter system. 3 years and going strong. When that goes Im getting the 27hp Briggs Turff Series,,,Since i have the muffler and wiring all set. These are commercial grade and 1/3 of a Kohler Command which I love btw...
As a hobby I restore older Cub and JD tractors and repower them... normally 318s and 420s with Onans.
Im in the process now taking out the caster wheel bearings and that has proven to be a PITA...
I have about 1300 total into the ZT,,,