1981 K30 to 1971 K5 drivetrain/axles

[KSJ]

I am looking for confirmation of my research please:
1981 K30- took complete front end, rear end, trans, tcase and drive shafts.
My research tells me I can bolt this directly into my 1971 K5 Blazer. I am putting in new leafs front and rear.
Is anyone aware of other mods that are necessary?
Thanks for any help!
KJ

 

[Bent77]

May need to move the rear perches (or not)

May need to move the shock mounts

the pinion on each of the k30 axles are longer by about an inch (will take some of the slip on the driveshaft) and the u joints will likely be different

 

[Fastereddie]

Others will chime in, but I “think” the rear spring width might be different on the axle. The rest will definitely bolt in. May need to relocate/mod crossmember depending on what you have/had.

Annnd^^^^ what speedy said about shafts haha

 

[diesel4me]

I know the first generation K5's did have a narrower rear spring pad spacing than the 73-87 trucks--but some 1 tons (dually's ?) might also have a narrower pad spacing,you may get lucky and they'll line up..

 

[Truckman4life]

67-72 truck rear spring spacing is narrower than the 73-87 stuff due to the spring hangers putting the springs closer to the frame. If you have an actual 1 ton rear axle though it should also have the narrower spring perch spacing and will bolt right in. Everything else should go in just fine. You may need to mess with things like motor mounts and trans crossmember and clutch linkage depending if you are doing anything like an auto to manual swap or vice versa or big block to small block or anything else like that. I know when I originally took apart my '72 I think the clutch linkage pivot ball on the small block was on the engine block and later on I saw one on a newer truck like a '74 or something and it was on the trans bell housing.

 

[imiceman44]

I am looking for confirmation of my research please:
1981 K30- took complete front end, rear end, trans, tcase and drive shafts.
My research tells me I can bolt this directly into my 1971 K5 Blazer. I am putting in new leafs front and rear.
Is anyone aware of other mods that are necessary?
Thanks for any help!
KJ

From what I know the 1 ton rear axle will bolt in on a 71 k5, the shocks will not, just the springs.
The driveshafts will need to be shortened since the length of the k30 is more than the k5.
Even the front driveline needs shortened because the front springs are shorter, putting the axle a little further back.
Front axle should bolt in fine and even the shocks.
The transfer case will bolt up fine, you might need to drill new holes in the frame based on what transmission you have.