14 SF 6-lug Axle for 73-87, what is the best option

[Mattchu60]

Hi All,

I have been planning to swap in a semi-float 14 bolt 6-lug axle. I thought that some K20's came with this axle in 6-lug version, but it seems I was wrong. I looked at a K20 once that had 6 lug wheels which is why I thought they existed, I wonder now if it was a K10 with k20 Badges on it.

I would really like to keep my 6 lug wheels, as the tires are almost new, but I need more strength than the 10-bolt rear can offer. This is a work truck that will have heavy loads on it from time to time.

Is my only option to go with the 88-98 SF rear from a Z-71 4x4?

I understand that the perches need to be removed and rewelded. What about the brakes? Are they drums or disc? I dont need disc brakes if they are drums.

If anyone has done this swap and can give me information on how to perform it, that would be great. I had done a lot of reading and there is some conflicting/blurry info out there.

Thanks

 

[Stroked]

I think they only came on the "light duty" 3/4 ton's. 2wd or 4wd.

 

[Kapdin]

I think they only came on the "light duty" 3/4 ton's. 2wd or 4wd.

As far as i know yea.

 

[Mattchu60]

My understanding is that the light-duty 3/4 ton K20's all got 8 bolt Semi-floating axles, not 6 bolts. Is that correct?

 

[Stroked]

I don't know if there ever was a light duty K20. But yes, the K20 and C20 from 81-87(I believe) got an 8 lug, semi floating 14 bolt. I don't know this for a 100% without a doubt fact, just stating my observations.

I'm talking about the 88-98 body style. You could get a light duty 2500 that had 6 bolt wheels. It had the 6 lug, semi floating 14 bolt.

 

[Kapdin]

yea we had 2 on the farm. a 1989 chevy light 2500 and a 91 gmc 2500 light and both had the 6 lug.

 

[GreaseDog]

88+ the 7200# gvwr 2500s got a 14SF, and the 8600#gvwr got an 8 lug 14SF, with a FF as an option. also keep in mind that the 2wd 6 lug 14SF is about 3"narrower. IIRC, the gvwr thing is the same on squares and the SF or FF rear axle.

 

[GreaseDog]

Also, the 6 lug 1/2 ton "Z71" 14 bolt is not a Z71 deal, it's option code F44 (heavy duty chassis). This option is NOT a part of the Z71 package. The Z71 package is shocks, skid plates, and bedside stickers.

However, I have seen some weird combinations, such as F44 trucks with the 10 bolt and an 80e (which wasn't available in anything under 8600#) to a non F44, non Z71 K1500, purchased new by a depends mother in 94 with a factory 80e and 14SF.

 

[TRokk]

Guys, I have a 3/4 ton back axle, 14b, 8lug with 3.73 gear ratio, on a 79 GMC High Sierra Jimmy however a 1/2 ton front axle with 8lug with a 10b GM Corporate Axles

 

[Jake_S]

The square 3/4 tons came with either a 14FF or 14SF (depending on the year and options), D44/Corp 10 bolt (depending on year of vehicle) and all are 8 lugs.
As stated above the 6 lug 14SF came in various 88-98 models, and I believe they are all drum brake units.

Jake