how strong is the 8 3/4 #741 case?

I have a 4.56:1 pumpkin for the 8 3/4 rear with posi. I'm 76 years old now and want to leave a street drivable car for my daughter who loves my 1970 Duster 340. I'll trade for your 2.94:1 pumpkin with posi if they are compatible. I'm in Diamond Bar, California. barry91765 at g male
Nothing wrong with the stock 3:23 gears