83 c20 upper and lower control arms on 68 c20

[ThomasW]

Can i swap the upper and lower control arms on my 68 c20 with new 83 c20 control arms?

[SCOTI]

Originally Posted by ThomasW

Can i swap the upper and lower control arms on my 68 c20 with new 83 c20 control arms?

The upper mounting studs for the cross-shaft could possibly be larger for the later model arms if doing a truck to truck swap. I would measure/validate the studs on your '68 & compare them to the '83 upper arm shafts.

I've never messed w/an earlier C20; only 73-87 & later models. But, I have done enough 67-72's & 73-87 C10's to know things changed for the 73 models:

*The bushings on the 73-87 C20-C30 are still the same HD set-up like the earlier trucks.
*BJ's will be different between drum & disc set-ups.
*The later model arms will physically swap over but will require the rest of the package to be updated as well.

[SkidmoreGarage]

I had a complete swap from a 1973-1987 c20 in my 67 c20. I didn't do it myself, but I did have to remove it all.

From what I have learned re-engineering it:

The upper and lower control arms will bolt up but you will need larger lower u-bolts (9/16)
You will need later model spindles, which then will mean ball joints/brakes/wheel bearings/etc.
I think you also need the correct tie rod ends for the later model spindles.

[Ziegelsteinfaust]

I have never swapped crossmember between generations, but if your wanting to swap the arms. With all the differences there maybe or could be.

Is he not better off to swap the crossmember too at this point?

[SCOTI]

Originally Posted by Ziegelsteinfaust

I have never swapped crossmember between generations, but if your wanting to swap the arms. With all the differences there maybe or could be.

Is he not better off to swap the crossmember too at this point?

Swapping the x-member makes it easier for ID purposes on what to use so 'yes'. But, swapping x-members between generations can yield other differences since the rails are slightly different.

[SkidmoreGarage]

My 67 c20 to later c20 setup used the stock cross member. I don't see why you would need to change it. I think that all the mounting points are the same.

[SCOTI]

Originally Posted by SkidmoreGarage

My 67 c20 to later c20 setup used the stock cross member. I don't see why you would need to change it. I think that all the mounting points are the same.

They are very similar. The C10's have a couple of bolt holes on the vertical surface of the frame that requiring 'ovaling' the holes for the hardware. The 73-87 C10 frame is also a little taller where the x-member is located which can impact which motor mount towers/stanchions are needed. It's possible these differences will also be the same for C20's

The main differences are usually the upper a-arm shaft mounting hardware & lower a-arm u-bolts being different sizes. The hardware sizes increased when the disc brakes were introduced on the later model trucks. The upper a-arm shaft mounting studs are also larger for C20's vs C10's.

[ThomasW]

Ok thanks for the input. The sizing all looks the same
So far Putting the arms next to each other (i have the front clip off). I plan on swapping the arms and using my original
Drums for now and later doing discs. The ball joints look the same size.
Should this work?

[SCOTI]

Originally Posted by ThomasW

Ok thanks for the input. The sizing all looks the same
So far Putting the arms next to each other (i have the front clip off). I plan on swapping the arms and using my original
Drums for now and later doing discs. The ball joints look the same size.
Should this work?

Drum vs. Disc BJ's showed different p/n's when I looked them up online. They might look the same but the numbers said they're not. I would double check if it were me.

[ThomasW]

Had a chance to to get this done today and the a arms matched up
Great. Everything fits nice. I added new springs and shocks. Getting the
Otherside done tomorrow.