Steering Knuckle & other part Identification

[gizmoduck81]

Hey everyone. Hoping someone can help me identify which parts the prior owner used on my 1963 GMC. The engine is out of a 1988 Suburban R20 (454) and I'm trying to figure out if the disc brakes and related parts are from the same vehicle or something else. I couldn't find any guides through search on how to identify these parts and looking up casting numbers hasn't really helped.

I'm specifically trying to identity the steering knuckle (spindle), upper ball joints, tie rod ends, and the crossmember (is it original?).

Brake info I know: Rotor is 11.86 x 1.25, 5 lug. Caliper is JB5

I have 71-72 c10 upper ball joints installed and they feel tight, but the cotter pin is above the castle nut, which obviously makes me nervous.

I ordered upper ball joints and tie rod ends for an '88 R20 and although the tie rod ends look right compared to what was installed (new above, old below in pic), the upper ball joints are different (old on left, new on right in pic).

Any help would be appreciated. Pics attached. Let me know if more info is needed and I'll provide when I can over the weekend.

Thanks in advance!

[PGSigns]

The a arms look like western chassis. The spindle and rotor look like 73 to 87 HD 1 1/4 stuff. The ball joints should be 73 to 87 C10. Now the tie rods will be from the same vintage going by the steering box and the idler arm. I would try this stuff first. The FAQ section has a lot of links to threads going over this swap. Everything under the front of my 66 is out of a late 70's donor truck.
Jimmy

[Captainfab]

The spindles appear to be '73-'87 C10 parts. I also see that the idler arm has been upgraded to what appears to be the same '73-'87 parts. So I would assume the OP used the entire '73-'87 front suspension except for the a-arms and including the entire steering linkage. This is what I always recommend doing.

An '88 R20 is a 3/4 ton with 8 lug rotors. What you are working with is 1/2 ton with 5 lug rotors.

[gizmoduck81]

Thank you both, PGSigns and Captainfab! The a arms are from Performance Online (Western Chassis). I swapped those on, which is what started me trying to identify the rest of the parts. I have ordered the 73-87 ball joints. Looks like the tie rod ends are the same, so I lucked out there!