Dual exhausts on 75 Scamp 318

[scamp80602]

This is down the road a few months, but how hard is it to put a dual exhaust system on a 75 Scamp 318? I believe 1975 Dart and Duster 360's came with duals from the factory, but I'm not sure where the cat converters were placed in a dual system. Has anyone done this conversion with success? Thanks!

 

[scamp80602]

After referring to my new-to-me 1975 Chassis Service Manual, I discovered that 1975 360's with dual exhaust had NO cat converters installed - only an air pump for major emissions equip. Must be a cleaner engine that the 318. SO, does anybody know how similar the 360 and 318 headers are for 1975's?? Will the 360 H pipe fit the 318?? That will tell me if I can use the 360 dual setup.

 

[H22A4]

The same manual also states that some 318 engines are also only equipped with an air pump only (much like the 360 Dusters). That explains why my '75 318 Scamp never came with a catalytic convertor.

Depending on how much $$ you want to spend, you could get an axhaust shop to make a dual system for you or buy one pre-done and mandrel bent. When I swapped the single exhaust for the duals on mine, I had the shop make it custom from the manifolds back.

If your state has annual emission tests, then you may need to rethink your strategy if you remove your cat and your car doesn't have an air pump.

 

[rumblefish360]

If you do dauls, you'll find there are kits out there or a shop can do it easy for you. No cats on those cars.