I know many of you guys are working on your GN's over the winter. I am looking for someone who has his exhaust system apart. The 84-85 hot air cars have a "all most square" exhaust flange on the catalytic converter where it meets the turbo down pipe. I need some information on the size of the flange, distance between bolt hole centers. I want to make a flange on my milling machine and make a catalytic converter eliminator pipe. I have my car in storage right now and can't get to it. Thanks in advance Mr. Buick