All depends. if you want to run a D300 you need a D60 out of a chevy or dodge, unless your gonna flip the 300 then you want a D60 from a ford. 78&79 D60's from f350 and f250 with camper package or snowfighter package will be the most desirable and the most costly. Here in the north east they sell for about $700 in OK shape, out west, where trucks don't rust away as much, they sell for far more. you could also run a 80-92 (93) f350 d 60, but it is a less desireable axle due to the limited amount of space on the drivers side axle tube. the 78-79 D60 perch width is about 32" and the later ford D60's are around 36" perch width. you can use newer D60 from a F350 93-98 but they are even less desirable because they are ball joint axle and not King pin axles. and after 98, they are those wierd metric 8 lug bolt pattern, ball joints and unit bearings.
The Chevy and Dodge Brakes, spindles and knuckles are more desirable because they are a bit larger and more durable.
For a rear axle, I would avoid a D60 all together, 14 bolt is the way to go. you will have to shave the housing, but the D60 will have to have the spindles machined to run 35 spline shafts and this "supposedly" a strength issue. A 14 bolt, pretty much stock will handle a 40" tire locked with out issue.
