swap steel rear trailing arm to late aluminium type

[graham c]

i want to swap my 1970 911 E steel trailing arms to aluminium type,are these a straight swap bolt in job, will the track width alter, and are the rear bearings the same inner diameter,will my E stub shaft and wheel hub suit the later bearing or do i need a complete rear bar with hub and stub shaft,i assume the radius arm i have on the E will bolt up to the aluminium arm, thanks

[Flieger]

You can put the arm on but will have issues with the dust covers hitting the heat exchangers and you need to modify the attachment boss for the damper.

Many advise against it on 1970 and 1971 models due to their unique rear chassis geometry (different from all other years).

Swap steel trailing arms with alu trailing arms?

[Evans, Marv]

I put them on my '69, and if I had to do it over again, I'd skip it. The amount of weight saved isn't that much, and unless you are going to be driving the car in a way to stress the trailing arms, the added strength isn't necessary. Inless the smaller rear beariings constantly fail (which they don't), the larger bearings arent necesary at all. I machined an inch off of the aluminum trailing arms I put on my car. The machinest wasn't too happy about it because it was a bit of a hassle for him, and he was an old Porsche guy from way back.