7 1/4 Rear End in 69 Barracuda

First I'd change the rear no question about it.
Second understand that the 8.75 rear from an a body will be a small bolt pattern (which is the same as your front 5x4), unless someone swapped them/re-drilled them. Now if you don't mind the big bolt pattern a b body 8.75 it fit as well but you'll need to move the spring perches in 1/2" each side and you'll need different rims with more backspacing but the b body rears are muh cheaper vs a body 8.75 (also finding the brake parts for a body 8.75 with stock setup is a real *****).
Third is the 8.25 rear from a 73+ a body (know this now the 8.25 ONLY came in the BIG bolt pattern 5x4.5), these can be found for cheap just know that the 2.71 ratio and down (numerically lower) is a different setup from the 2.91(? Or is it ratio 2.94 either way 2.9+ is the one to grab) and up (numerically higher) but again the 2.9+ is the rear you want and here is why. You can acquire more part for cheap/junk with 2.9+ ratio 8.25 a body rear. Once you get that 8.25 a body rear go to the junkyard and find a 1996 and older jeep grand Cherokee. Once found open the rear diff cover and see if it is a limited slip diff. If so take out the limited slip unit and gears as well (most of the time the jeep will have much better gears than what's in the a body 8.25). If the jeep also has rear disc brakes take that setup as well. All these parts you just took will bolt directly to the a body 8.25 rear. once done This will give you an a body 8.25 with some very decent gears with a limited slip unit and rear disc brakes.

Finally, if you opt to upgrade to the either the 8.25 or 8.75 will need to do a few things.
1. You will need new/different leaf springs
2. You will need new/used shock mount brackets for the 8.25/8.75 because the 7.25 has a smaller diameter tube compared to the 8.25/8.75 (which are/share the same diameter tube).
3. You will need to have your driveshaft shortened or replaced for the 8.25/8.75 rear.
4. This one is optional depending on what brake setup you have up front (drum) you might wanna look at converting to front disc brakes. If you want to keep the small bolt pattern you can get the scaredbird setup or the factory K/H setup. If you don't mind converting to the big bolt pattern just look for the 73+ setup. The big advantage the big bolt pattern has over the small bolt pattern is a much much wider wheel/rim selection (which also means a bigger tire selection), much much cheaper/easier to find brake parts, less maintaince, and will just a caliper adapter (don't even have to disconnect the brake line) you can run 11.75" front rotors vs the stock small bolt pattern 10.87" rotors which more stopping power. If you go this route of big bolt pattern brakes, just get the sliding calipers off a 77-78 roadrunner because they have a bigger piston diameter in them.

I know way more info than you wanted/needed to know but you said you daily drive the barracuda and just but upgrading to front disc (and rear disc or bigger rear drums) you'll have a much much better stopping distance. Safety first enjoy.