Axle swap

[Chevyman63]

Can anyone tell me what modifications, if any, are needed to install axles from a '79 truck onto a '72 Jimmy.

[Burt4x4]

The front will bolt right in, your brake line fittings should work but may need to change the bajo bolt.
The rear your going to need to cut off the spring perches and move them inward adout 1 1/2" and probly the shock mounts will need changing...depends.
Other than that..can't think of anything else other than brake harware??

[Chevyman63]

Thanks for the help Burt. Now to pass on the info and see if it is worth it or not.

Thanks to you as well Mark. I knew I could count on everyone here.

[Yukon Jack]

Is the 79 a 1/2 ton or 3/4 ton? If 3/4 ton, you will need a conversion u-joint for the rear driveshaft to axle location.

When I did a 3/4 ton swap to my 70 K5 I found my stock hard lines wouldn't bolt up to the rubber lines. I went ahead and just made up new hard lines with the right fittings.

Burt's dead on about the rear axle spring perches, unless your 79 happens to be a 1 ton, then the spring perches are in the right position.

It's a pretty straight forward swap.