Electrical problem

[rbuckin111]

You guys have been great at helping me diagnose problems in the past. I hope you are willing to help me with another. After putting in a rebuilt engine in my 64 GMC, I am having a couple of electrical problems. One is the tail-lights flash continually but not the front, and I don't have 4-way flashers. When I turn the turn signal lever right, the left goes out and I only have the right turn. When I turn it left, both continue to flash. I could only get it to stop by taking out the flasher, but now I don't have turn signals. All the rest of the lights seem to work normal

My temp gauge is acting strange too, in that it starts out just below half when cold and goes up almost to hot when it is at operating temperature. I am certain that it is not accurate. It used to work fine with the other engine. I even put the old sensor in the new engine thinking it was something with the new sensor. But no change.

Anything you guys can think of that I might check to correct these problems?