I do not know about a rally dash.
what people did was find a similar size sun meter volt meter and disassembled the gauge.

depending on how close you want it to look, some took apart the old one and used that face plate on the sweep portion of the sun meter gauge so it would still look the same.

others found a place that could replicate the font and repainted/stickered over the old so it showed correct voltage with the old gauge face but new gauge guts.

you would have to see, and I am guess a more rounded sweep, might be an issue.