I would not do it. They both advance the timing. If both are advancing the timing in a different way I would think that the timing advances would stack causing it to be advanced way too far. If you could get the EZ without the timing advance then you could add some more fuel at one of the boost settings on the EZ that should stack on the fuel the VA adds, a little more power with some smoke control. All in all, I really think it would be a waste of time and probably damage the engine. Just MHO.