Manifold bolts should not be over- or under-tightened, so use this type of wrench with a foot/pound scale
[DOC] [TLE] Best Torque Wrench for the Money: 2016 Reviews & Guide - [PAR] A Torque Wrench can be defined as the tool that is used to apply torque and 
fasten ... to measure torque needed to fasten the bolt or nuts without over 
tightening them.