Will later rear alu trailing arms fit a 72/73 911?

[POR71]

Hello there,
Got a bit of a worry,well actually not me but a friend of mine is looking to put rear alu swing (trailing) arms think they're 1976 's (so later type), the aluminium type onto his 911 S year 1972/1973
WILL these fit?
Will the wheel and shocks face any problems?
Will the wheel be corectely alligned in the rear wings? In other words are they different in lenght and on...
Go on and give me your thoughts on this....
THKS

[john walker's workshop]

they fit ok. i recall having to shorten the mounting for the lower shock bolt 3/4" or thereabouts. used a sawzall.

[Flieger]

They fit much better on a 72 or 73 than a 70 or 71. I think they are a direct bolt on for 72 and 73 because didn't the 74 get them from the factory? There were no significant geometry changes in the rear chassis between those years.

[joefrantz]

Here are mine.
76 arms on a 73 tub.
Direct bolt-up.

First picture is at full droop.
Second picture is at simulated ride height while playing around with suspension travel/wheel fitment.
The shock dust cover is off in the second picture because I was measuring the travel. They fit either way.

[john walker's workshop]

maybe it was an earlier car that needed the shock mountings shortened.

[Flieger]

70-71 at least need mods. You were probably thinking of that.

[Trackrash]

I don't think there is a definate cutoff for when Porsche went to the longer shocks in the rear. I've seen a 72 that had the longer shocks, and a friend has an original 73 with the shorter older style shocks. Both had steel banana arms. So in your case you will just have see if mods are required.

[fintstone]

Certainly aluminum on a 74...would expect it would be a direct swap to a '73.

[Trackrash]

Certainly aluminum on a 74...would expect it would be a direct swap to a '73.

That's exactly what I was telling a friend of mine who has a 73. He was parked next to me and we looked and his training arms and shocks were identical to the ones on my 71. So go figure.

[joefrantz]

Here is a link to Sherwood's (911pcars) Excellence Magazine article on the Rennlist site.
This article, along with the additional links included on page 5, contain just about anything you need to know about aluminum trailing arm compatibility and installation.

UpgradeAlloyControlArms

[POR71]

MANY THANKS,
He was very pleased with the results you send...

[fintstone]

Joe's link to Sherwood's article was pretty comprehensive. Amazing what a resource that this site...and Pelican's can be.