74-70 axle swap

[47Firetruck]

I've got a 70 C-10 with the factor 12 bolt rear and 6 lugs. I also have a 74 1/2 ton parts truck with a 12 bolt rear and 5 lugs. Can I swap the 74 axles into the 70 12 bolt housing? Or should I just weld on new mounts and swap the whole diff? Thanks for the help!!

[Longhorn Man]

You may be able to do it, might not. All depends on your 70. Some were wide, some were not. All you have to do is pop off the cover and pull the C-clip and give it a shot.

[kaycee]

My 70 was a narrow 1 so I had to make a spacer for each side.I have been told they made a wider 1 sometime in 70,thus making it a direct swap.My 69 & 70 r the same size 55 1/2" from backing plate to plate if using the newer axles you might need to use the drums allso I had to. The spacer I used was a homemade 3/4" on each side between the housing & backing plate I used 2) 3/4" steel plates so I could keep it some what sealed.I was lucky enough to use plasma cutter,drill press,4"grinder so it was not hard at all

[47Firetruck]

Thanks for the replys guys! When I get back in the states I'll have to see what happens, hopefuly it will work.

[Blue Beard]

Isn't the 74 a leaf spring setup...?

[47Firetruck]

Blue Beard

74 is a leaf spring setup, but you can buy or torch off the mounts from the 70 and weld onto the 74 housing. I'd just by the new saddles myself. I've found them on the net.

[70short/step]

So the spring mounts on a 73 and newer leaf rear end are different than the 67-72 leaf rear ends??
70short/step

[Longhorn Man]

With no papers here, I have to say I remember some one saying the spring perches are not the same width, nor same distance.
I may well be wrong on this, I have never paid much attention to the leaf spring 1/2 ton stuff.