Roger as a fellow timber lover, doesn't a nice piece of wood lift the overall beauty of an engine!
Would some rubber feet or a rubber mat put on the bottom of the plinth work in anchoring her down and lessen her tendency to want to dance around?
Jim, I "thought" I would go one better and make the entire contact surface of the base "grippy". I smeared clear silicone sealer with a putty knife over the entire underside of the walnut base. It actually works very well on a surface like formica, but the somewhat lumpy greenish cutting board surface I use to protect my benchtop meant the silicone only made intermittent contact and hence the engine still "walked" a bit. Four rubber feet might actually work better on an uneven surface! It was a test...one I probably won't repeat.
And...yes, a lovely piece of wood really accents a nice engine in my eyes as well.
Rog
ps....thanks to the nice comments from others.