ok so i have a 91 crx si with a b16 that im trying to put a 4-1 header on it. i have a omni power test pipe and invida cat-back. the problem that im having is that the collecter on the header is "2.5" (i measured it and it is 2.5 but with the gasket thing its closer to 3). the flange on the test pipe is close to 2.7. the problem is the bolts will not match up. the flage on the header is bigger than the flage on the test pipe. also i dont know if the header will even work cause im moving the o2 sensors further down on the exhaust. if anyone can help. please tell me how to fix this small problen. oh by the way its still obd0
