1986 Nissan 300ZX red hot exhaust manifold!

My mechanic changed the timing belt and he mentioned that the old belt was advanced one tooth, now, the car runs strong but in order to do so I have to advance the timing through the distributor all the way to the right otherwise if I move it back just a bit it will run like crap and the problem is that both exhaust manifolds are getting red hot! Do I need to take the distributor out and move it one notch back?

Thank you!

Ivan