They go on mowers and pulling tractors all over the world! This Kit is for ALL the K301 and M12 Kohler engines, which means that it will fit all the K301s regardless of the suffix. I will beat anyones price. CUSTOMIZED TO MEET YOUR ENGINE REBUILD NEEDS….. KIT INCLUDES THE FOLLOWING: 1- New Piston: PISTON COMES IN: Standard. 030 over, Chrome Piston Rings. Wrist pin and Keepers. 2- 1- Connecting Rod. CONNECTING ROD COMES IN: Standard, or. 4- Intake Valve 1.372″ Exhaust Value 1.125″ New Set of Points. 5- New Spark Plug. 12hp K301 These measurements are not for machine shop use. The machine shop must have the new piston to bore your block. 020………………………………3.395 +. 030………………………………3.405 Standard rod…………………… 1.500″. 010……………………………….1.490″. 1.480 Anybody can Rebuild a Kohler engine themselves. I will also give the instructions on how to properly install your connecting rod. The most common reason for premature engine failure on your rebuilt engine is an improper rod installation. In my other auctions, I also offer high Quality, cost saving tools and other COMPLETE Engine Rebuild, Refresh Engine Rebuild Kits to rebuild your own engine, so please check out my other auctions for tools, lawn, tractor seats and other rebuild kits. 020 connecting rod in place of the std or. ยท Thanks, Kevin Thanks for Looking! The item “MASTER REBUILD KIT FOR 12HP Kohler, K301 WithFREE ITEMS” is in sale since Tuesday, July 23, 2013. This item is in the category “Home & Garden\Yard, Garden & Outdoor Living\Lawnmowers\Parts & Accessories”. The seller is “bakt4kids” and is located in Wauseon, Ohio. This item can be shipped worldwide.