Home » Tony’s Tips » Articles » Fuel Flow Diagrams for the Popular 6BTA 5.9 330/370 DiamondsFuel Flow Diagrams for the Popular 6BTA 5.9 330/370 Diamonds Fuel Flow 330-370 Diamond Fuel Flow 450 Diamond Cummins Combo Block Part Option 3-way combo block split oil Fuel in & Fuel out Very Common Fuel drip area-Lower plugs that serve no purpose