Hi Jim H, welcome to Red Square!
I assume you mean a rebuild kit for the K181. I haven't actually done a full tear-down of the engine (only the upper half). I ordered all gaskets/hardware piece-by-piece from wherever I could find it (amazon, fleabay, partstree, etc.). I'm a little picky when it comes to head gaskets... make sure they have a compression ring. The 1st one (OEM!) didn't have it. The Stens one (465-310) I ordered did...go figure!
It already has a 0.030" piston in it. Fortunately it only smokes at start-up...probably due in large part from me using 5W30 syn.