Gas Gauge and Speedo Question

[MBurns326]

ok I really need some help here guys......

First My gas gauge and oil pressure gauge are not working. Strange thing is that they are both on the right side of the panel, but the gauges on the left side (temp and speedo) are working just fine....well see the bottom......What could cause just the two on the right side to quit working. The oil pressure is really important and I would like to get it back working.

Second my speedo has been off for....(well it's a 1971) probably 38 years. Bigger tires were put on it when my grandpa bought it new. It's probably 25 miles per hour too fast, and as a result it is putting miles on twice as fast as it's supposed to. How can I fix that? Do I need a new cable or what?

THANKS!!!!