need 8 1/4 advice

I put 3.55's in mine along with a sure grip bought through my regional Mopar Performance Parts Dealer. They offered a 10 % "racers" discount and free shipping. Best deal I came up with. Gear change will be your cheapest and easiest solution. For your use the 8.25 would be great and your already set up for it. With the 8.75 you'll also have to modify the length of your existing drive shaft.