Are 1971 lower control arms same as 1970?

[375instroke]

I feel stupid for asking this. Dude on craigslist insists they are the same, but I would have thought they would be different.

[ACUDANUT]

Yes...Everything is the same, except 73 and up.

[hemi71x]

FYI
All lower control arms are the same on the 70-74 E Body line of cars.
And all lower control arms for the 62-72 B body line of cars are the same thing, as the 70-74 E Body cars.
The only thing different is if a sway bar mount tab is welded onto the LCA.
The 66-69 B body tab is welded on near the ball joint stud hole, and the 70 -72 B Body cars, and the 70-74 E Body cars, have the tab welded on near the center of the arm.
Other than that, all the control arms will interchange, and fit into all those cars.

[Hard Charger]

just a side note here

the UCA.s in my 68 charger was the same in my 72 challenger except for the size of the ball joint. the 72 had a slightly larger hole.

[ODZKing]

2535878-9 w/o sway bar
2535074-5 with bar

According to the part numbers 73 is different from 74 as well.

[Nacho-RT74]

73 and 74s are diff just because the ball joint... 73 are threated, 74s and laters are pressed in

[375instroke]

Found my new K-frame and LCAs.  Pulled the control arms off a '71 Roadrunner and found something strange.  First, even without sway bar mounts, '70 and later control arms are smooth through the I-beam area, whereas '69 and earlier has a strengthening rib formed into it.  This rib would interfere with the sway bar mount on the '70 and later bars.  My LCA cracked around the torsion bar socket.  One of the '71 LCAs had this area removed.  It was dark, and I couldn't see what else was different, but it looks like the socket was riding against the thickness of the stamped metal.  Wonder if they found out pressing the metal at that sharp a bend radius was weaker than having a thicker flange ride against the torsion bar socket.  Below you can see the flange I'm talking about and the crack that developed at the bend.  The sockets are a loose fit in them, but in the later LCA without this flange, the socket fits much tighter.  This was also on one arm only, so I don't know if this changed in '71, and they used an old arm on one side and a newer one on the other side, or if one was changed through the years.  There was a set on a '70 charger that matched, so I took those instead.

[ACUDANUT]

Sway bar mounts are different, but would not kill the project. Glad you found a pair.

[Brass]

Glad you found a K-frame and arms!