1977 aspen rear end

Remember too that the F-body 8.25" is wider than an A body 8.25". The F-body 8.25 is about 59.6" drum to drum, or about the same width as a 65-67 B body 8 3/4.

So, the perches have to be moved, the driveshaft will need to be shortened, and if you're trying to max out the tire width you'll need more backspace. Although with a Dart Sport you should still be able to use stock offset rims and run tires up to about 225 without any issues.

You can take a look at the specs here, it's listed as an 8 3/4 chart but I have some specs for the F-body 8.25's on there too.

An accurate 8 3/4" rear axle width list