I had a three-wheel stand that worked fine with a sbc V-8, but it felt very wobbly with an assembled 261 on it. I gave it (the stand, not the 261) away and bought the better stand (four fairly widely spaced casters) that Cummins Tool sells. It feels very solid with the 261 engine. However, I did need to drill some additional holes in the arms and adapter plate to be able to position the engine with the cg near the rotation center so that it would rotate easily.
Another approach for "safely" mounting a six to a stand was described in the "Tech Tips" of the Sept/Oct 2003 issue of the 12 Port News by Ron Sneddon. He fabricated an adapter plate to mount the engine sideways, to keep the cg near the rear wheels. Ron also describes a method for finding the cg of the block assembly.
Hoyt, II# 922
