3.00 Conventional Rear Axle

How do i know if my 1969 Cougar XR7 has possi rear end?

Chock the front wheels, jack up the rear with both wheels off the ground. Make sure the parking brake is off. Put the transmission in park. Turn one of the wheels. If the other turns the opposite way, then you have an open diff or a very worn out Trac-Loc. If you can’t turn the wheel because it wants to turn the driveshaft which is in locked in Park then you would have a Trac-Loc. Also, both wheels would want to turn the same direction.
What should the car have? Do you have a Marti report or a means of decoding the door dataplate info?

Yes

The other wheel turns the opposite way

What do i need to do to make it a possi rear end? And where in the Marti report does it tell me what rear end is on the car?

For Marti Reports go to the website, and it is self explanatory.

Posi, is not as simple. YouTube will have many videos. Look for Ford 9 inch

Traction-lock rear ends were very rare in these cars. I’ve had 20+ 69’s and only two were traction locks. Even big block cars were often open rear ends. Your door tag will tell you what you had originally. If it was an AC car, probably had a 3.0 open.

My bad. Crawl under your car and look to see if the metal data tag is attached to 1 of the bolts on the rear center section. Someone on here can probably decode it for you. You may be able to decode it via the internet.
https://www.fordification.com/tech/rearends_ford02.htm

pegleg 3.00, one wheel peel.

Looking at the Marti Report, it sounds like you have a very pretty Cougar. Do you have any pics to post?

Cool pic. Nice garage.

Saw that car for sale on FB. Looked like a good buy.

Correct its a nice car.