I just put a stock Grand National exhaust in my GP. I used a free flow cat with a 2.5 in and out and made a 4 bolt flange to meet the stock pipe instead of spending $300 for the stock cat. The only problem I encountered was the hanger that is mounted on the rear transmission support is 2" too far back to meet the flange. I made the mistake of matching the flange with the hanger but the pipes ended up to be 2" too far back to install the pipes that go over the rear axle. The overall length of the cat with the flange has to be 20". Other than that it's a perfect fit.
I know it's not a true duel but it sounds nice and if the exhaust flow was good enough for a turbo vehicle that was one of the quickest production vehicles it's good enough for me and besides the whole system (except cat) cost me $50.00..
I know it's not a true duel but it sounds nice and if the exhaust flow was good enough for a turbo vehicle that was one of the quickest production vehicles it's good enough for me and besides the whole system (except cat) cost me $50.00..
