Bell tech drop spindles (issue?)

[Hybridcx]

Hello everyone,
I picked up a set of belltech's 3120 drop spindles real cheap last week. I have a 72 GMC 1/2 ton (2wd) and it would seem these are ment to fit that year chev/gm. My issue is when I went to install them my outer tie rod ends were too small. I did a bit of digging and figured out I needed C20 tie rods. Does anyone know why this is? Is this typical? I just want to make sure this isnt going to cause me issues down the road. Thank you -Matt