What trucks came with Front Dana 60s:
GM
1977-87 K30 1 ton 4wd
1984-88 CUCV
1988-91.5 V30
All GM / Chevy versions were passenger side differential, regular rotation (low pinion) gears, disc brakes, 35 spline inners, 30 spline outers, internal style hubs, and kingpin knuckles.
Dodge
1975-89 D-600
1992-93 D-600
1981-89 D-700
1992-93 D-700
All these Dodge versions were passenger side differential, regular rotation (low pinion) gears, disc brakes, 35 spline inners, 30 spline outers, and kingpin knuckles. 1979-89 versions had external style hubs, with the earlier versions with full-time NP203 Transfer cases having external drive flanges, and later models having external lockout hubs. The external lockout hub bolt pattern is 8 x 3.960". The 90-93 versions had internal style hubs just like the Chevy and lockout hubs. One caution with dodge applications, is you have to be careful to avoid the Dana 61 front axle. 1987-88 and 1991-93.5 Dodge D600 and D700 also came with Dana 61. More info on the Dana 61 later in the article.
3/4 Ton GM Trucks have 2 front axle options, Dana 44HD (70s) and 10 Bolt (late 70s and early 80s)
1 Ton GM Trucks came with Dana 60s
14 Bolt rear ends can be found in 1973-87 GM 3/4-tons
Alxe ID Chart Link:
http://www.cdmfabrication.com/bbpics/axlechart.jpg
The axles you are looking at will be a direct bolt in to your 79 Blazer. The only modifcation you will need to make is your ujoints. 3/4 and 1 ton run 1350 and 1410 size ujoints vs 1/2 ton 1310. So you will need to make new drivelines or get the ujoints that have two sizes in one(as a temp fix).
Hope this helps