Ronzoni,
The item you describe is called a pinion snubber. They were (are?) big with the Mopar crowd.
My BetaCat leaves the line like a 13.0-second car -- real hard -- but then again the combination of the CJ factory high-stall converter and the non-factory 3.70 gears will do that, LOL. Anyway, since Beta leaves the line so hard, it has a tendancy to wind the rear springs up a bit while squatting down back there as she digs in. The rear end is wrapping up so much that the front of my rearend housing, where the pinion gear is, smacks the floor. The little balancing weights on the driveshaft are scraping on the floorpan/driveshaft tunnel and are wearing through! I corrected my little problem by using a pinion snubber.
Did you ever look at a Ford 9" rearend and see what looks like a plate steel shield on the top of the pinion where the driveshaft yoke is? It bolts on to where the pinion carrier bolts to the center section. It has a small rubber bumper on it. That's Ford's pinion snubber. It is mostly used on pickup trucks. Nobody says you can't use on on your Cougar!
It will keep the rearend from wrapping up as much as BetaCats does and sort of acts like a traction bar. The only thing is, it won't stop wheel hop if your tires start bouncing alterately like traction bars will. But then again, they don't hang down and make the car look dorky either for a street driven car.