time for new axles!

[SC74]

That's going to be the hard to find and expensive one! The balljoint types are a lot easier to find and usually less expensive, but don't offer enough room on the driver side tube for the arms.

Well, I found the BOM on the axle, it's 603381-5. Turns out it is a HD FF D60 that came from a 73/74 F-250 3/4 ton 2WD truck, not a 79 F-350. Not a big deal in this case, just nice to know.

So what should I be looking for exactly, an 85-91.5 Ford F-350 king pin axle vice a 78-79 F-250/350 king pin?

Source: http://www.pirate4x4.com/tech/billavista/60_front/

King Pins are preferred for strength, but if you're not going to go hardcore off-road then balljoint front end will be adequate. You will just have to find a way to mount the arms - it has been done so I'm sure there are plenty of people who have pictures and advice on how to overcome the short drivers side axle tube. Maybe CAGE's SAS bracket will work since it is not as wide. I don't think that the years of king pins necessarily matter, just the king pin vs. balljoint.

I've also read, re-read, and continue to use that article on Pirate for help with the 60's.