Coolant leakage (Barracuda -69)

There has been some leakage by the water neck - see picture. I thought this was due to a bad gasket. Because of this I changed the gasket (Fel-Pro 35145 - Fel-Pro Water Neck Gaskets). Afterwards I took the car for a test drive and it was worse than ever - lots of smoke and coolant all over the place under the hood.

Any ideas what I should try?