It's just easier to narrow an 'early' D44 vs the 78/79' models is all, and better chances of finding a heavy tube version.
+1 It is just as easy to narrow and you do get the thicker tubes. Mine from start to finish took about 3 hours.
To Junkie: I will not got round and round with you over this, we all know of you and your love for TTB. I stated my reasons for SAS swap which are all valid, and the reasons to stay with a TTB. The hubs are real on a D35 in that you have to lock them, but they are weak and dont seal worth a damn, o-ring, silicone or whatever. The steering is far superior on a SAS, stock, lifted to the moon, or anything in between. If enjoy tire scrub with constantly changing toe, that's all you bud. As far as not holding an alignment goes, that is my experience with stock Rangers as well. After a good thrashing my steering wheel always ended up in a different spot than when I started earlier in the day. Give me your BII for an hour and I'll show you what I'm talking about
As for comparing the D35 beams to 3/4 ton axles, these are some awfully weird looking spring pads:
Hagan, this ^ is the ideal axle to start with when building a high pinion D44. 76-77 F150, 0.5" DOM tubes and welded on C wedges.