I've seen pictures with 2 bolt holes as well as only 1 on the legs. Also have seen some with longer feet where the legs mount to the block with a single hole or cut off very short at an angle. Since I don't have a complete set of attachments I have no idea of the legs length, anyone have an original they could measure? The plan at this time is to make the rear attachment first then with block in place (shop has block with lift plate installed) to make the front attachment made to fit. My goal is not for 100 percent reproduction attachments but a quality product to use Clayborne stands. Here's a link to a late 60's Clayborne catalog that a Barn member has on the National Ford Tool Collectors website, they had adapters for a variety of engines back in the day.
https://fordtoolcollector.org/clayborne-engine-stands/