You might need a special tool to remove the gear carrier. I don't know the year changes but, some 7 1/4 rears had shims to adjust the carrier preload and back lash (like the dana, and 8 1/4). You need a case spreader to remove and install the carrier/shims. Other years used threaded adjusters (like the 8 3/4) but you need to go through the axle tube to turn them. There is a torsion bar that has the right size hex ( I think "B" body) that can be used as the tool. I didn't have the correct size torsion bar, so I welded a large nut to a old "A" body bar, and ground the flats on the nut, until it fit the hex in the adjusters.
Personal opinion: I ran 7 1/4's for years, on the street and drag car with slicks and nitrous. and they are not as weak as people think. That said I wouldn't spend much money or time on one, today. It is getting hard to find parts for them. As for sure grip, you might see a SG unit for sale, but I have not seen any replacement clutches for sale in about 8 years. If you do find any, they will be pricey.