1968 barracuda temp gauge and fuel level inop

I need to go to radio shack tomorrow to test it further.

OK if you're going the do it yourself route for testing... 23 ohms is the center of the gauge, not 27.
A solid state regulator will not live very long in a corrupt circuit. There are manners in which the original mechanical limiter failure is corrupt so bend the little thingy doesn't fix anything. And in most cases, a solid state regulator will provide needle movement only. Gauge accuracy is gone. Good luck though.