What is the correct water pump ratio for a LA engine? Then there is the fact that some water pumps have 6 blade rotors, some have 8 blade rotors, Some have a backing plate on the rotor...... Yes I realize its my job to understand what I have and I will get to the bottom of it and solve the puzzle.... Got a 63 MM Stant USA Made gutted thermostat in the water neck now as I am still testing some things trying to make what I have work.