With a little work, a volt gauge can be put in place of the original amp gauge. the wiring must be changed. There's a thread with more info here somewhere. I did several of these conversions for rally panel owners. I used a Sunpro volts gauge, transplanted the original needle onto that volts gauge too. I still have some custom gauge screen decals with the volts scale on them. The downside is 1 nice new screen and repainted needle doesn't look so great in a cluster of 4 where others still look their age.