Cuda won't start and have tried multiple avenues. Need help!

You should also have a ground cable that runs from the rear of the right head that goes to the body. These were put on prior to painting at the factory to secure a good ground but the previous owner may have installed it after painting, check this connection...it should be attached with a sheet metal bolt and a toothed washer.
IF you are using an aluminum intake and have the ground from the battery connected to an intake bolt check it closely, the bolt and intake are dis-similar materials and are prone to corrosion.