The 7 1/4 rear is not as weak as most people think. I have been running the same 3.91 SG 7 1/4 since 1974. It has been in 5 different street/strip cars. Now resides in my 66 Valiant that runs mid 13's at 94 mph in the in the 1/4 mile. Has slicks, and does 1.79 60 foot times. Also have a 4.56 SG 7 1/4, and a 5.13 SG 7 1/4.
But I do agree about using a stronger rear, if the money is about the same. On a street type car, I would opt for a 8 1/4. Good deals on "A" body 8 3/4 rears are few and far between. A early Ford Mustang V-8 8 inch rear is a inexpensive and viable swap into an "A" body.