70 vs 71+ ball joints. ID help

[gvnick]

I bought my truck (69 GMC 1/2 ton) with the front already converted to discs and drop spindles. How do I identify what year ball joints I have? I understand he could have gone either way with the conversion depending on which spindles were used.

Thanks for any input.

[hubcapboy]

For some reason this interchange is incredibly hard for me to wrap my head around also. I'm reposting the compatibility from here (http://67-72chevytrucks.com/vboard/s....php?p=4462868) to start for anyone who stumbles on this in 5 more years:

Upper Ball Joint:
Grouped by Differences:
C10
*71-72
*73-87

Lower Ball Joint:
Grouped by Differences:
C10
*71-87

This is parsed down to just C10, and just disc spindles. So the good news is the lower ball joints should be a slam dunk. For the upper ball joint, I have a factory fresh Proforged 101-10046 (the 73 and later upper) which I'll happily measure to compare against yours if you end up needing the info. I would also mention that I got a great response from the sales@proforged.com from Zack, who is the same guy who pops up to represent them on forums, and said that he could provide a list of dimensional differences if provided with a list of years. That might be your best bet, because it's coming from a manufacturer who'll actually be providing the part?

[hubcapboy]

OOO jackpot. Info from here:

http://67-72chevytrucks.com/vboard/s...d.php?t=384288

Ball joint measurements

72 upper. OAL 2.750, thread length 1", thread 5/8-18",taper length 1.150, minor dia .625 major dia .815

72 lower OAL 2.85, thread length 1.32, thread, 11/16 dia, taper length 1.12, minor dia .880, major dia 1.06


I tell you what, if you don't match this, give me your measurements and I'll tell you if it matches my '73 and up set!

Edit: Crap that might just be for a C20. I told you I was bad at this. Don't say I didn't warn you.

[gvnick]

Thanks for the reply, thats very helpful. I'm gunna assume mine are 70 and earlier style. I'll measure them when they are apart.

Was hoping it would be as easy as different size nuts used, so that they could be ID'd installed.