I just replaced a failed 3.0 with another 3.0 w/48k. Bolted on 1999 Ford Taurus 3.0 DOHC exhaust manifolds (flow much better), 2 1/4" pipe leaves each manifold, stock upstream O2 sensors are plugged in, pipes cont. into a single late model Dodge truck V-8 cat. (dual 2" inlets, single 2 1/2"...