I bought my 64 with a Stock 440 8/3/4 lasted 10 passes put the Dana in 1994 still there and cover has not been off since. You put them in and forget them for years, literally. By the way, when done you’ll have the same money in both, fords are more $ but they do have better gear selection
When I built the Dana I used the 8-3/4 35 spline axels, housing ends, bought used 4.88 gears and spool and truck housing. When done I might’ve had $300 in it. A friend bought an S60 for his Duster, right at $2000 from Dr Diff, setup and ready to install or it you scronge for parts the housing is around $600 from Strange and you fill in the blanks.