Need Exhaust Recommendations

Here's the scenario. The '71 Dart has a 318 that the PO had an aftermarket 4bbl induction installed. Besides a Flamethrower coil, that's it for the mods. The car still has single exhaust on it. I want to put dual exhaust on it (no headers). Because the Dart is what it is, I am trying to do this on the cheap.

Every exhaust shop I've been to wants to put new pipes/mufflers on it and I am getting prices in the $510-$600 range (which isn't in the budget). I don't mind spending this kind of money on one of the nicer cars but I have told myself that this needs to be done as cost-effectively as possible.

I started thinking really cheap when I thought that I could just have a passenger pipe run and then figured out that I would still need to get two new mufflers since I do not want to run two different mufflers.

One other possibility is that there is a gent selling a complete setup off of a '73 340 Dart Sport (one piece pipes from the flanges to the factory exhaust tips). Granted, he doesn't know what mufflers they are (they look like OEM replacements) and I believe the flanges/headpipes are going to have to be replaced/reinstalled since the angles are more than likely going to be off.

BTW: '73 340s used 360 exhaust manifolds, correct? Do they by any chance have the same headpipe flange angle as a 318? If I could just bolt these up, that would be fantastic. Can anyone think of any other issue(s) with using this exhaust on the Dart?

If anyone close by has any old exhaust pipes (especially a pass side) off of an A-body, let me know. This goes for exhaust tips to. They don't need to be OEM tips, just have an opening like one. I might as well add in mufflers too (center inlets/offset outlets with 2"-2.25" openings).

TIA