Cougar should be the same as a Mustang of the same year, they're both fox bodies.
My girlfriends son has a 89 gt Mustang that we put a 351w (5.8) in.
It has BBK shorter headers. They were a tight squeeze especially near the steering rod, I had to dimple them a bit there on one tube but they fit. Also they bolted right up to the stock H pipe that we used on the 5.0 which was friggin amazing.
I'll see if I can find a part # on them for you tomorrow, I'm at work now, cant ya tell??
Cp