I getting ready to put headers and true dual exhaust on my 77.  Is there anything I have to watch out for with emissions?

I would say it depends on your state to start with. If you were in Ca. you would need headers with a CARB number on them, ( California air resorces board), They would also need the bungs for the AIR system. In my state, NV. the only places they smog cars is in Washoe Co. and Clark Co. which is Reno and Las Vegas. All the rest of the counties do not have manditory smog inspection. I can't think of anything else that would apply. Check you state regs.

My county doesn't have manditory smog inspections. I was worried about how the car will idle or run without the AIR system on the car.  Is there anything else tied in to the system?  Oxygen sensor ???  Also the bracket for the AC bolts into the exhaust manifold.  Thanks for the repley.

 Donnie 

I have a '78 L82 and installed a true dual exhaust system, though I kept the cast iron exhaust manifolds. I removed the EGR and related plumbing (the AIR pump was missing when I bought the car), and the car runs great. There is no oxygen sensor.

You'll need to adjust the carburetor, timing. etc., anyway from the work you're doing as you're changing performance parameters.

You'll likely have to modify the a/c bracket if it bolts to a stock manifold. A speed shop should be able to take care of that.

I think the 77 uses the smaller R4 A/C compressor? If so, the original bracket will work with the headers, you'll need only a stack of washers or for better looks a spacer neatly cut from a piece of pipe under the bracket to fill the space originally filled by the manifold. Put headers and duals on my 79 years ago. Runs and sounds great. No emissions testing in my Illinois county either, but I have antique plates anyway.  Mike