WAYNE C. - K241 & K321 heads are the same. Things changed like spark plug location, the bosses where the head bolts pass thru can be different heights, and there may be subtle differences in the combustion chamber. But they all fit the 10, 12, & 14 HP engines.
Most people sand down the sealing surface with wet/dry paper & a glass plate or other smooth hard surface when they warp.
My old K241 had a head warped almost 1/8" when I got it, machine shop trued it up. I can't say the head never leaked, but it never blew another head gasket, When I'd start the engine it would "Whistle" which meant it was time to re-torque the head.
There's no problem doing head & port work on a "Working Tractor", I did a lot of cleaning on the intake & exh. ports on that K241, ran great for 1400 hours. On the K321 I built to replace the K241 I went a WHOLE lot farther. Problem with taking too much off the head on a "Flat head" engine like the K-series Kohler comes from reducing the flow area from the ports & valves to the cylinder. You can increase the compression but KILL the flow.