79' Blazer 1/2 to 3/4 ton conversion

[mac907]

Hello all, I'm fairly new to the 4x4 community. Having settled in Alaska my interest has evolved from GM muscle cars into something better for all seasons, so the K-5 sounded like a good fit about a year ago when I bought my 79'. I didn't really know what to look for so I ended up paying $4,000 for a 79' Blazer with a descent body that had 8" of lift, an offroad bumper with 8 ton winch, 39" tires, and ............3.73 gears. I put a few hundred miles on it and parked it until now after realizing the pricey work ahead of me to get it running properly without lugging around in low.

I just scored a nice set of axles form a 76' 3/4 ton Chevy (Dana 60 front & 14B F/F rear) with 4.10 gears that included wheels and 35" tires for $750. I'm doing the install next week and I'm wondering if there's any other mods I should do while doing the axle swap. I have the Offroad Design rear disk brake conversion in the mail that will let me use my original front disc brakes from my 79' as rear brakes on the 14B F/F axle.

I eventually plan on doing cross-over steering, but can't afford that right now. Are there any other simple/affordable mods I should look into doing while swapping axles?

 

[paratrooper307]

Better check that front axle. If it's a Dana 60, it came out of a 1 ton. 14 bolt full floaters were in some 3/4 tons, but front axles for a 3/4 are either a Dana 44 or 10 bolt. That and a rebuildable D60 usually runs at least 600 alone. This is important because the spring perches are spaced differently on the 3/4 / 1/2 ton axles and the 1 tons.

Make sure you have a conversion u-joint (447) you will need it to mate your 1/2 ton driveshaft to the 3/4 ton rear. Are you planning on leaving it at 8 inches of lift, or lowering it down some? With 35's, 6 inches or 4 with some trimming, works better, and the higher you lift these short wheelbase trucks the more driveline alignment issues you have. If you are thinking about changing the lift this is a good time to do it.

Although not absolutely necessary, you may want to swap out your brake master cylinder with one that matches the larger brakes.

There will never be an easier time to work on your axles, so this is a good time for new seals, repack/replace bearings, new brake parts, and a good clean up/paint.

 

[6.2Blazer]

As stated above, a '76 K20 would not have a front Dana 60 axle from the factory.....both from the fact that a K20 did not have it and '77 was the first year for the D60. However it could have been swapped in.

The rear 14FF is a good swap. If the front axle is actually a D44, which was the factory axle for that truck, you don't gain much except for the matching 8-lug bolt pattern and gears for the year.

4.10 gears are a very minor difference as compared to 3.73's. If you kept the same tires you would have a hard time noticing the difference, but if you went to the 4.10's and swapped to 35's at the same time there would be a significant difference.

 

[mac907]

Thanks for the input so far, I really hope it's a Dana 60 cuz I actually buckled down and just stretched the heck out of my budget to order a Dana 60 crossover steering kit.

The brakes on the front axle were pretty bulky and wouldn't allow any smaller wheels than 16" if that means anything. I'll have to double check tomorrow with someone more knowledgable after I get off the grave shift to make sure that I indeed have what I was told I have.

The guy I bought the front axle from just relplace a u-joint and axle shaft in the "illeged" Dana 60, so you'd think he'd know what he was ordering/replacing the parts in. He runs a snow plow company and does a lot of work with the 4x4s in his fleet, so my fingers are crossed that I do have a Dana 60 that was pulled from a modified 3/4 ton.

 

[mac907]

As far as the lift goes, I plan on removing the body lift portion of it which is pretty ghetto. It's a 2" hockey puck body lift that was actually made with NHL hockey pucks that have a hole drilled kinda in the middle. There is a fair amount of trimming already done to my fenders, and I will be using the 35's that came with the axles since they still have about 70% tread on them.

 

[owenst7]

Dana 60 knuckle: Note the lack of balljoints, and the bolted kingpin/trunnion bearing caps in their place

 

[mac907]

Thanks 6.2 Blazer and Paratrooper307, you were spot on and the front end was a Dana 44.

And thanks to Owenst7 I was easily able to identify a suitable Dana 60.

I should have it all together over the next two weekends and will post pics. I'm definitely looking into these threads before I do any other future mods and appreciate the help thus far.