1969 mercury cougar offer up doesn’t provide the option of 1969 mercury cougar
The body is straight gas a fairly new paint job, it has a supped up 302 boss. There is alot of new parts. Starting with the exhaust is new the headers and mufflers are new ,no rust underneath has been POWDERCOATED, new brake lines, brake booster, RADIATOR, water pump,valvecovers,carb,electric IGNITION MSD, IGNITION SWITCH BATTERY, i upgraded the PULLEY system to a serpentine belt. Please serious buyers only price is not set in stone. Please dont waste my time and by making low ball offer
You lost me at " it has a supped up 91" MUSTANG 302 boss". 
Glad they got rid of those pesky cowl/tower braces. So roomy now.
I don’t see a price in your listing…
So what exactly has been powder coated…the entire underside of the car? If so, how, as the whole car would have to go in an industrial oven. Hard to do without being on a rotisserie.
Not trying to tear you or the car down, just trying to get you to provide more info and possibly more pics to help anyone interested in discussing a purchase with you.
Include info like: is it a standard model or XR-7 or Eliminator; what type of interior is in it, standard, decore, or XR-7. How many miles are showing on the odometer? How fresh is the motor, recently rebuilt or done many years ago, or never rebuilt? What kind of transmission is in it? (C4, C6, FMX or TL 3 spd or TL 4 spd or something newer?)
All we see right now is mostly shots of an engine that looks like it has been driven a lot and has sat for a while. You mentioned a new brake booster, but what is shown looks pretty old and not fresh at all… again, not trying to put you or your car down, but we are seeing conflicting information. The one shot of the exterior of the car looks ok, but many more pictures are needed to show the whole car for a potential buyer to get interested.
This is a very helpful group of people on this site and we only want to give you some quality feedback to get you on the right track.
Since you didn’t post a price, all you are likely to get are low ball offers. 
It’s listed on Craigslist for $12,000. SF Bay Area