1971 verse 1972 and newer lower ball joint.

[Accelo]

1971 verse 1972 and newer lower ball joint.
Correct me if I have the application incorrect.
Picture are the two different joints.
Had a mix up as my 70 has the lowered spindles that require the new style ball joint.
Another $50 mistake.
So here they are for you to compare side by side.
The newer one is the blue one.

[toolboxchev]

First I would not trust Napa's Data for parts.

They will sell you an Fan Motor for your Non AC truck which in turn will cook your electrical wiring in the cab.

Sure you can get parts there......

[tdangle]

Per Rock Auto, C10 for both 71 and 72 call out the same part number. I use them as a reference for part numbers and then also verify with Autozone, and Orielly autoparts

[tim_mc]

In case it helps someone, here's what I used on my '67 to update to '73-87 components (reused '67 control arms):
(2) Upper ball joints, '71-86 C10, Moog K6117T.
(2) Lower ball joints, '73-86 C10, Moog K6136.
(2) Outer tie rod ends, '73-87 C10, Moog ES409RT.
(2) Tie rod adjuster sleeves, '71-87 C10, Moog ES2004S.

I reused my '67 center drag link. El Camino inner tie rods match the smaller '67 drag link taper and the larger shaft of the '73-87 outer tie rods:
(2) Inner tie rod ends, '73-77 El Camino, Moog ES2020RLT.

For completeness, here are the other parts I used when rebuilding the control arms/steering:
(1) Idler arm, '67-82 C10, Moog K6096T.
(2) Control arm shaft, lower, 63-72 C10, Moog K6147.
(2) Control arm shaft, upper, 63-72 C10, Moog K6098.
(1) Power steering gearbox, 3-1/4 turn, Lares #1075 remanufactured.

[Steeveedee]

When I got the kit to put disc brakes on the front of my truck, the new ball joints had the splines. They were too big to press in. Dug out my Machinery's Handbook and scoped out the tolerances for a press fit and hit the splines with a mill file until they would make a press fit. Not worried about them falling out, but in 45 years when they need replacement again, I'll let that mechanic use his skull sweat on the problem.

[tdangle]

Originally Posted by Steeveedee

When I got the kit to put disc brakes on the front of my truck, the new ball joints had the splines. They were too big to press in. Dug out my Machinery's Handbook and scoped out the tolerances for a press fit and hit the splines with a mill file until they would make a press fit. Not worried about them falling out, but in 45 years when they need replacement again, I'll let that mechanic use his skull sweat on the problem.

I just did the disc brake upgrade myself. I used a kit from POL. Lower ball joints went in but what a pain. Even worse, they were way to tight, even though I greased the hell out of them. Started creaking and return to center did not work. After less than 50 miles I replaced both sides with a Moog lower ball joint for 71+ C20. Still a pain with the ball joint press. Works much better.

[Accelo]

Thanks for the all the replies.
I measured both the ball joints. The splines ball joint was .010 larger, over the splines, than the one I removed. I pulled the lower A arm and used a 10T press. It went in without issues.
Here is a picture of the Napa box.

[BigBird05]

According to rock auto 71 & 72 take the same ball joint. A Moog K6117T. One of those ball joints you have is incorrect.