The place I bought mine from used to advertise in MCG year ago. I can't recall the name of the company, but I probably have the receipt somewhere.

The reason I know they are slightly shorter than the Barracuda ones is they used to offer the 70 340 Dart tips with a different part number than the others. If you run across any survivor 340 Dart pictures the exhaust tips don't poke out past the valance nearly as far as the reproduction one size fits all tips that so many cars have today.