The B737-3/4/500 AMM 71-00-00 p280H states:
Let the engine become stable at low idle RPM and make a check for these "approximate" indications:
N1- approx 21.5%
N2- approx 60%
FF- 550-950 PPH or 250-430KGPH
EGT- 450.C-650.C
ENG overspeed is dealt with else where in the same chapter aswell as overtemperature.