Cluster issues?

[Huskers]

Hello again.......still chasing issues with gauges. Working on an 81 with a 350 and I previously posted about it not heating up. I completely went through the cooling system and I believe it's actually working properly now, however, my temp gauge is still reading a little goofy. I could hot rod this thing around and it'll heat up properly but the gauge only gets to the first mark when in fact it's actually at operating temperature. 

I'm starting to think it might be a problem with the cluster because some of the other gauges read a little funny too.

The oil pressure gauge is pegged at 60 when idling or driving most of the time but sometimes it will actually read properly after it's been driven a little and then when we just idle again, it pegs at 60..........or sometimes it'll actually read a pressure although it's usually high. I've replaced the OP sender already.

 

The volt meter used to read right at 11-12 volts so I went ahead and replaced the alternator since it was cheap. Now it reads like 17 V which I don't believe one bit. 

The fuel gauge reads overly high which i originally diagnosed as fuel sender unit but now I'm having second thoughts about rather it actually is the sending unit.

 

All these gauges seem to be all over the place so it seems like the cluster is the common denominator here. What are the symptoms of a bad circuit board? 

 

Do I just have a bad ground perhaps?