Looking for some Differential advice
Save it money, go to a rpm/tire size, final drive ratio calculator, cut rpm down with taller tires
That's a great idea, but from the maximum that will fit, to the smallest anyone is likely to install, is only about the equivalent of One gear size;
from 2.76 to 2.94 is about 6.1%, and from 2.94 to 3.23 is about 9%
The tallest tire that the 72 Dart will accept is about 28 (maybe), but to install it, the axle may need to be moved back. So let's say a 27, cuz I don't think there is anything between 28 and 27. The shortest tire that one might install would likely be a 24.5 .
from 24.5 to 27 is about 9%. But 24.5 will be useless against a 408stroker.
So while the idea is a good one, it sorta depends on from where you are starting.
I've had a few Darts of those years, and I sorta recall installing some 225/75-15s, which, by the math is 28.3. But they have to be well inside the tubs to not rub on the rockers.
