Lazarus,

If you have a 750 lb or a 1000 lb style stand (no matter what brand), it will be unsafely unstable with any stovebolt engine (216/235/261).

The 2,000 lb style stand works safely if you change around the mounting fingers to bolt directly to the block. This is safe and stable, and allows rotation of the engine/block.

What type/style of stand do you have?