From everyone I've spoken with, exhaust heat comes in quicker, water heat is easier to regulate.
When you say 'regulate', what exactly do you mean? Do you a way to keep the manifold heat less than the engine temp?
I ask because I found that I was boiling the fuel out of the carb after it was parked if the coolant temp was around 180 deg. I put in a cooler thermostat and the problem was solved, but now I don't know if I'll have enough heat when the ambient temp is around zero.
