The mighty five horsepower, air cooled, gasoline fueled, side valve, single cylinder, four stroke, centrifugally governed, cast iron barreled, aluminum headed engine roared back to life!!!
And I was able to finish mowing my modest little lot, hopefully for the last time this year.
As stated, I used my 'product improved' cylinder head, sanded/lapped smooth and straight (over 1200 strokes on 220 grit wet-or-dry) and the 'new' style head gasket. I also switched from the stock seven head bolts (five bolts & two studs with the 'product improved' head) to seven studs and SAE flanged nuts w/stock [thick] washers (called "worshers" in some states)
and re-torqued after running for a short time.
I checked with the old timer who ran the Cadet Cub repair shop and after confirming I had the 'old style' 5hp Kohler engine, recommended torquing to spec and then running "for about an hour" and then letting it cool and re-torque it. The gas tank mounts right over the head so I had to jig-rig a 2x4 and bungee cords to hold the tank away from the head so I could see if it came loose or some other malfunction. I was surprised that the cooled head took about a half turn to each nut to re-torque.
So now it's done and we'll see next Spring if it starts and I mow again or buy a new mower. I'm sort of hoping it won't so I can buy one of the orange compact zero-turn tiller-steer mowers that my neighbors seem to have so much fun with.
Either that, or stuff a 4-cylinder 1974 Honda motorcycle engine in the Cadet and see how long that lasts.