On a V8, it might be worth it. Not sure if it would on the 4.2. It does have a vacuum line from the intake manifold to the crankcase but the vent hose under the resonator box connected to the valve cover, which is the one that spews the most crud. You can even find a pool of oil in the box sometimes. There's just one thing if you do add a catch can to the valve cover is that the PCM is programmed to compensate for the throttle body getting gunked up. So engineers knew that this was a flaw in the system. Then you have the vacuum line. So is there oil mist going through that one too? It might need two catch cans.