Should I use "Oil Restrictors" in my engine?

No, Crane Cams does not recommend the use of oil restrictors. The oil is the life blood of the engine, not only lubricating but cooling the engine components as well. For example, a valve spring builds in temperature as it compresses and relaxes. This increase of temperature affects the characteristics of the spring material, and if excessive, will shorten the life of the spring. Oil is the only means the spring has for cooling.