can anyone tell me the torque on exhuast manifold bolts for a 1978 70hp evinrude model#70873. I have manual and it says exhuast housing to powerhead is 18-20 ft lbs it does not say what to tighten exhuast manifold bolts to there is a chart for torque on diff size bolts is this what i am supposed to go by. thank you for any imput