Duster with b body 8 3/4 wheel set up
3-1/2" to the leaf springs?
So it sounds like you have the springs relocated to the frame rails, but without a mini-tub?
B-body 8 3/4 axles work well in the Duster/Demon/Dart Sport bodies and even the Barracuda's, because they have more room to the quarter. You just have to run the appropriate backspace. Figuring out the backspace isn't all that difficult, you can just go to the rear axle width sticky An accurate 8 3/4" rear axle width list , take the width of your B-body 8 3/4 and subtract the width of an A-body 8 3/4 with BBP axles, and divide by two. Then take that number and add it to a know combination that fits an A-body 8 3/4 with BBP axles. Say, a 15x8 with 4.5" of backspace and 275's (which is pretty common combo for a Duster). Doing the math for an 8" wide rim and that combo gives you a backspace of ~5.65". For a 9" wide rim it should be more like 6.1" with that particular combo. Not something you're going to find really in a 15" rim, but easy enough for a 17" one or bigger.
I have a 68-70 B-body 8 3/4 in my Duster with a 1/2" spring offset and was able to run 295's with a little bit of quarter lip trimming with 18x10's and a 7" backspace (+38 offset).
3-1/2" to the leaf springs?
So it sounds like you have the springs relocated to the frame rails, but without a mini-tub?
B-body 8 3/4 axles work well in the Duster/Demon/Dart Sport bodies and even the Barracuda's, because they have more room to the quarter. You just have to run the appropriate backspace. Figuring out the backspace isn't all that difficult, you can just go to the rear axle width sticky An accurate 8 3/4" rear axle width list , take the width of your B-body 8 3/4 and subtract the width of an A-body 8 3/4 with BBP axles, and divide by two. Then take that number and add it to a know combination that fits an A-body 8 3/4 with BBP axles. Say, a 15x8 with 4.5" of backspace and 275's (which is pretty common combo for a Duster). Doing the math for an 8" wide rim and that combo gives you a backspace of ~5.65". For a 9" wide rim it should be more like 6.1" with that particular combo. Not something you're going to find really in a 15" rim, but easy enough for a 17" one or bigger.
I have a 68-70 B-body 8 3/4 in my Duster with a 1/2" spring offset and was able to run 295's with a little bit of quarter lip trimming with 18x10's and a 7" backspace (+38 offset).
Has to be a 3" relocation, only way to have that much space and have the wheels inside the quarters with those specs
