I Using coolant to "heat" the Offy manifold is a lost cause- - - -it's cold when the manifold desperately needs exhaust heat- - - - -during warmup.
Jerry
OK, so I'm not crazy for wondering what's the point of using coolant. By the time the coolant is up to tempt, the manifold probably is as well, or at least well on it's way. I really couldn't quite figure out the benefit of that system, but thought maybe I was missing something.