I called around the local engine shops today. Most of them don't have the tools and reamers to do the valve guides anymore. Finally, I called one of the dealers that happens to be right on my way between work and home. He said he could get the Briggs valve guide inserts, and dig up the old special tools somewhere in the back of his shop, --- OR --- he could sell me one of his new old stock Briggs motors sitting on the shelf for years, never run before, that he bought from an older shop owner who sold his inventory to him years ago. So, I am picking up an 8 HP B&S with recoil start, one year warranty from the shop owner, for $275. I couldn't pass it up. Saves me a lot of stress and time for about what the rebuild parts and valve guide work would cost me. Yeah, I'm giving up 4 hp over the original engine, but I think my Snapper with 28" deck was overpowered anyway at 12 hp. I never really did manage to bog it down much when it was running good, and the old engine probably wasn't putting out the rated 12 hp even then. Thanks Restrorob and the rest of you for pointing me in the right direction.