Rebuilt my 7.25 rear end and bad news....

In a perfect world, i might swap the rear end. But the fact is that i'm leaving this slant 6 in there as is for the next 10 years at least. So its not like i need a more powerful rear end. Plus i don't have the money, time, or space to swap the rear end.

This thing is a daily driver. And ya, I've done a few google searches and found a few things, i just thought i'd throw it out to y'all guys. See if i can find some high quality parts out there. I don't want to get stuck with cheap chinese parts or something and have this problem again in a few years. Or worse yet, change out the ring and pinion and still have a whine.

3.90 and 4.11 probably will no do. This car is for gas mileage and highway speeds. So I'm thinking 2.93? Thats the lowest one i've found. Is there much diff between that and a 3.21 gear ratio?