I got these off of eBay and was excited to replace my crappy, old and bent flanges. I just discovered that they will not fit as the inside diameter of these flanges is approximately 1.4 inches where the 4 into 1 has a 1.5 inch diameter. Did I just figure why the 4 into 1 set up is a performance add on? Any advise on making these work for my set up?