Repower Toro 139-0603 with Rehlko/Kohler KT724-3002 is the LPAC or KT745-3103 is the HDAC upgrade.
AI: "Based on the engine specifications for the Toro 139-0603 (2P77F) Twin Cylinder Engine, the corresponding crankshaft is part number 127-9255. This crankshaft features a 1-inch (approx. 25.4mm) diameter PTO (Power Take-Off) end, which is standard for many residential zero-turn mower engines.
Engine Model: 139-0603 (Toro 2P77F)
Diameter: 1" is typical for this 24.5HP engine)
PTO Length: Approximately 3-5 inches from engine seal
Use 130-0676 Muffler
Use of the RP1 is recommended for configuring the wiring.
https://www.smallenginesuppliers.com/shop/html/images/small_engines/kohler/parts/rp-1.jpg
One tip to keep in mind, you might need 4 of part number 25 086 672-S, 3/8-16 x 1" self taping bolts to mount the New Kohler (Rehlko) Engine down. Block will come with 4 blind, not tapped holes. these will zip right in without having to try and tap the block.