Today’s engine stands were never meant to hold our beloved Stovebolt sixes. They need longer legs both length wise and side to side. You can stabilize it somewhat by putting a chain/strap around the head of the stand and ratchet it up to a rafter to take the pressure off but not place the full engine weight on it. Remove the pin, rotate the engine, put the pin back in but keep the chain/strap in place as long as the engine is on the stand, no matter whether it’s upside down or right side up. Or, as said above, put longer legs on the stand. Hillbilly engineering at its finest.