5.2 Magnum exhaust manifolds on a Valiant?

In the Mopar Muscle article about the manifolds I'm nearly positive they were using a set of older Magnum manifolds for the test. The older ones (92-93) had a 2-1/4" outlet whereas the newer ones only have a 2" outlet. The newer ones may fit better since the outlet pipe is smaller but they don't flow as well. Since the artilce shows all the manifolds being within 10 hp of each other if I weren't going to use headers I'd use what fits the best.