Hello I saw your post about the nut you bought from McMaster-Carr for the OBX straight flange downpipe to make the SAS fit and was wondering if you could tell me the size I am having the same dilemma, thanks in advance
Wouldn't your ratios be in cm2 not cm3. first ratio would be (64.5^2)/(61^2)= 1.118, second ratio would be (71^2)/(61^2)=1.354
Looks like you math is correct, your units are just wrong.