Yep, they are still trying to beat the SV singles to death because of a few engines that had mistorqued top cover bolts, without locktite, and a few that broke the counterweight alignment rod which would break the bottom of the block dumping the oil. Later versions had gone 700-1000 hours easily. Anybody hear about failures on the 5400 series engines that was also a bucket style engine that replaced the SV singles. Didn't hear about those bolts coming loose or cracking the block.
Anybody remember the TH Triad DOHC engines. Seems nobody talks about that engine. The one were the timing belt cavity would fill full of debris damaging the belt, and required a debris eliminator hole on the bottom of the cover below the crankshaft pulley. Or if the engine overheated it would slide the steel cylinder liner down until the top piston ring would get above the liner and then the downward motion of the piston would drag the liner down into the crankcase resulting in it breaking both rods.. And Kohler paid for the Triad to Command conversion in Walker and Grasshopper mowers.