To SAS or not to SAS

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GMC Burbalade

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I used the kit from Offroad Design, and a Dana 50 from a 2000 F350 Super Duty.

The Offroad design kit I highly recommend. It's a little bit pricey, but still a LOT cheaper than some of the other companies.

The Super Duty axle (50 or 60) I do NOT recommend unless you're building your own brackets and swapping to a Super Duty rear axle as well. For 99% of applications, I'd recommend the 85-98 Ford Dana 60s. The earlier models (92 and older I believe?) have king pins and are easier to setup crossover steering. While the knuckles are weaker on these, there's more aftermarket options for knuckles. The newer 93-98 models have ball joints, which are a LOT easier to service/replace than king pins, but tend to wear out faster.
The Super Duty axles use a metric lug pattern, unit bearings (more expensive, but easier to replace) and have a wider spring perch width that no one makes a kit for.
 

nobears

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IIRC the 87-91 F350 Dana 60 is a 36.5" spring center isn't it?
 

nobears

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I think IG I do this I'm going to use a kingpin Ford Dana 60 and 52" springs along with the Off road Design or Sky SAS kit. Both look like they'll lift the truck 7-8" with a stock spring (Fabworx got ruled out as it looks like you have to run their springs at $550 a pair). Now as I'm trying to keep the truck fairly low what are y'all's thoughts on using an aftermarket drop spring (think low rider truck) at say a 2-3" drop to keep the height down?
 

GMC Burbalade

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A low SAS has low clearances, low clearances with soft springs can lead to problems. When I first put mine together I didn't have much room between the diff and pitman arm. If you want to keep it reasonably low, I'd just stick to 3" brackets with a 3" lift 47" spring. That should put you right at 6" without having to worry too much about clearance or spring rate. The 52" springs are good for higher lifts but at the height you want, you're not going to be able to make use of the extra flex they'd provide.
 

GMC Burbalade

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That they will, but the extra lift you don't want. They're soft, many say too soft. Too soft and low clearance isn't a good combo. It's not like the 47" springs have a terrible ride, it's just not as soft as the 52s.
 

michael hurd

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Most 3/4 tons had 56" rear springs. They'd give you a little more lift as well. I ended up swapping my overloads for AALs which worked well to cut down on body roll, but gave me another 2+" of lift. Essentially the same thing as building a 3/4 ton 52" leaf pack.

Or if the secondary springs aren't too long, you could use a 52" main spring with the rest of a 3/4 ton or 1 ton pack.
Or double up on the second or even second and third springs... Options are endless.

You could mix and match, but it's not as good as an engineered spring pack: each leaf is a specific length to properly support the one above.

Eaton Detroit spring has a bunch of good information on leaf springs, as well as coils, and it's free:

http://www.eatondetroitspring.com/spring-tech-university/ask-the-spring-guru-2/leaf-spring-tech-questions/

Spring Tech 101 download :

http://www.eatondetroitspring.com/wp-content/uploads/st1014.pdf
 

Jrgunn5150

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A low SAS has low clearances, low clearances with soft springs can lead to problems. When I first put mine together I didn't have much room between the diff and pitman arm. If you want to keep it reasonably low, I'd just stick to 3" brackets with a 3" lift 47" spring. That should put you right at 6" without having to worry too much about clearance or spring rate. The 52" springs are good for higher lifts but at the height you want, you're not going to be able to make use of the extra flex they'd provide.
This...

47's don't ride awfully or anything, or flex terribly... Remember, every single K-series had them up front from the factory from 73-87 (91 for the Blazer,Jimmy, Burban), they just aren't the most awesome easily available spring...

For what you want, stock 47's will be fine. Only 3" of lift with the Offroading Design brackets.

Also 47's have better approach angles
 

nobears

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So the Offroad design brackets and a set of stock K-series 47" spring should sit me at 3" lift?
 
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