total timing reading accurate with no load?

Interesting the manifold vacuum advance is working for you. I've thought about trying it on my 360 but the way it is now it's very happy with 20 initial and 39-40 total (9:1 comp, aluminum heads, high altitude), if I added the 14 or so degrees of vacuum advance at idle I'd probably need to back down the initial and then readjust the mechanical advance limit so total timing stays the same. Kinda doesn't sound worth it, anyone think it's worth a shot...?? It runs perfectly the way it is now.