PN 13201 Master Calibration kit contains over 130 pieces to facilitate tuning of all four VRS-4150 fuel circuits. Suitable for carburetors that use gasoline as a fuel (not E-85). Contains four each of main fuel jets 62, 64, 66, 68, 70 and 72 for quick global adjustment of the fuel curve. Four each of the air bleed 10-32 jets .024, .028, .032, .035, .040, .055, .060, .065,.070 and .075 allow quick small changes to the main, intermediate, and idle circuits. The 6-32 jets .020, .025, .031, .035, .055, .060, .063, .070, .073, .076, and .083 allow fuel changes to the idle, intermediate and power enrichment circuits on the metering blocks. 4 window power valves in 5.5 and 6.5 opening vacuums change the transition point from Cruise AFR to Power Enriched AFR. Finally, .033, .035, and .040 accel pump squirters change the duration of accel pump fuel from leaner and longer to a quick discharge.