Thanks for keeping us posted, chippy17. I'm glad you got the parts you wanted. Sounds like you will now have to ream the valve guides to the exact size of the oversized valve stems - it may be cheapest and easiest to get this done by a mechanic who has the right reamer and prior experience, because first-time attempts to use a reamer often give bad results. Whatever you do, do not attempt to use a drill-bit.

Because it is your father's old mower, I can understand that you have a sentimental attachment to it. Otherwise I think most of us would choose not to spend $215 plus, to repair an old rotary mower with a Tecumseh engine.