Early vs. late control arms

[gringoloco]

All thing being equal i.e.: spindles, springs, brakes, etc.- if I swap my early(71-72) control arms out for late(73-87) arms, will my alignment be affected?

I know the upper balljoints are a different diameter, but will still bolt in place. The shaft pivot points will obviously be the same, but are the balljoint distances from the shaft equal? Also, is the bottom of the spring pocket on the same plane; given the same spring will there be more/less drop with one or the other?

The obvious answer is: "Just go get it aligned". Just want to know if I can bypass this.

Thanks -Chris

[gringoloco]

Here's a diagram expalining what I mean:

[PBFAB.COM]

I snapped a few pics for ya on a comparison. Looks like the spring cups are a little different, but as far as my tape measure says the distances are the same (that's what I though, but I wanted to verify first). Be careful though... that tape measure has been known to be off by an inch every now and again!

[gringoloco]

Thanks Nate, that's exactly what I was looking for. The difference in pockets is actualy why I'm swapping. The 73-up is much shallower/wider, allowing a shorter cup which means more drop and a few more PSI for the front at ride height.

I also seem to remember something about the cross-shaft locating stud being diferent between the early/late crossmembers. Anyone run into this?

[jlaird]

one difference that I notice is the angle of the shock mount. The later style would come in handy for me right now because I wanted to fab up an upper shock mount, but the shock would hit the upper control arm. So I might have to adjust the positioning of that lower shock mount to something like what I see in the picture of the later control arm. sorry, just rambling...

[Spray-Bomb]

On mine I have 85 A-arms & never got to see the 67 ones, cuz the PO had already changed them out for some later year

From what I have heard, the earlier A-arms are narrower than the later ones & it makes sense to me

The locating pins on mine do not line up !!! & if the A-arms were narrower I would have less clearance issues

Hope this helps mang

[BACKYARD88]

My 85 arms lined up fine with my 71 crossmember locating studs. As long as you don't ahve a sectioned crossmember you should be fine.