The more I think about it, the less tempting the 2.5" system sounds. Its meant for long headers with 3" collectors which means I'll need some extra pipe anyway. So I think I'll just go with some standard bends. I've also pretty much abandoned the idea of dutra duals, at least for now.

I've read about people porting out the exhaust manifold outlet to 2.25" and getting some good results. Can anyone speak to what kind of performance gains this will bring? Also, which years had exhaust manifolds with space for an O2 sensor?

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'66 Dodge Dart

Here is one place that has aluminized steel and stainless steel $220-$300 plus shipping

http://waldronexhaust.com/cart/index.ph ... =61_36_125

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1964 Dart GT

Thanks, but that seems like a lot for standard pipe bends. I was quoted a better price for custom exhaust work at a local shop by a guy I trust.

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'66 Dodge Dart

I just posted it as a price comparison, not to buy from them.

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1964 Dart GT

It is about the same gain as removing the stock four blade fan and going to an electric fan. Both mods help response from 1500 rpm on up.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG