1800cfm is one big Throttle body!
Best I can find on Throttle body flow per size...
65mm Throttle Body 745 CFM - 3.125" OD
70mm Throttle Body 830 CFM - 3.125" OD
75mm Throttle Body 915 CFM - 3.125" OD
80mm Throttle Body 965 CFM - 3.500" OD
90mm Throttle Body 1170 CFM - 3.750" OD
95mm Throttle Body 1450 CFM - 4.250" OD
105mm Throttle Body 1520 CFM - 4.250" OD
The 2012 and 2013 COPO's have 102mm and the 2014 COPO has a 90mm Throttle body.(427 motors)