Alternator wiring

Yes, the voltage regulator I have installed is an electronic voltage regulator that looks like the old style ones. I thought I had to run a wire from the second field post on the alternator to the ignition post on the voltage regulator?

No.

I thought you only grounded the second field post if you were keeping the old regulator

You are keeping the old (style) regulator, it's just yours is electronic and not electromechanical now. Hookup is identical to the original '60-'69 regulators.

Could my problem with the amp gauge be because I didn't splice into the wire but instead used a splitter to attach the 2 wires to the ignition side of the voltage regulator?

You have miswired your charging system because you have misunderstood the electronic regulator swap you did. Follow directions (in this thread) and get your car back on the road, or keep on asking the same question again and again and the car stays dead. Yer choice!