600 recommends MAC tools CT-100-03 gauge, CT-100-02 coupler & release valve, CT-140 14mm hose assy (long reach) with a CT112 adapter (12mm). Be advised there are a number of things that will effect your readings such as engine temp, hose length, valve timing and altitude. No matter what it reads when you test it, the test the tech person does is what you have to go by, their gauge is God be it right or wrong, they are not required to have it calibrated. Been there done that! MAC tools also has a test set I belive the number is CT-125, Sears also has a nice set for around $50.00.