I cooked this up at the shop last week.
My spare engine for the race car was just sitting on the floor of the truck, and I have several other engines laying about the garage that need to be more easily portable.
I have a couple of small rectangular dollies but I wanted something purposebuilt with a lower center of gravity.
My design supports the engine from the square bosses on the bottom of the heads, provides clearance for attached stub pipes and other peripheral hardware, and can have a piece of plywood under it to support the case as well if desired.