Gauge Cluster Issue & Radio Issue

[nomad0231]

HELP! I recently restored my 67 Chevy (can be seen on here). I'm having issues with my instrument gauges though. My tach won't go above 1500rpm, no matter what and my speedometer gauge bounces around. For instance, if I'm going 60, it doesn't stay on 60, it bounces around 60, up and down. Anyone else have any issues like this??

Also, I'm wanting to put in a new radio (there is not one in there now) I don't see a red power cable for any radio and know these can be bought for like $8. If I buy one, how the heck do I hook it up and is that really all I need to install a newer type radio, like the USA model?? And where would I install speakers for a stock look, but good sound?

All help is greatly appreciated!