Manifold bolts should not be over- or under-tightened, so use this type of wrench with a foot/pound scale
The four basic types of torque wrenches are beam style, click adjustable, 
dial gauge... [DOC] [TLE] How to Use a Torque Wrench - How to Tighten Lug Nuts [PAR] Apr 25, 2011 ... Wheel lugs are probably the most common type of torque application.