aluminum trailing arms update on a 70 911

[jgilliam914]

What do I need to know? Is it as simple as swapping out the arms n the e brake mechanism? What about sway bars?

[TRE Cup]

Well.... yes and no
1) The arms will bolt up, e brake pieces interchangeable
2) The 69-71 chassis has a different angle shock crossmember in the chassis
3) the 69-71 utilizes smaller diameter rear shocks, with smaller diameter mounting eyelets on the bottom. You need 72-89 model rear shocks
4) The shock angle is different
5) most oem/ ssi heat exchangers will rub on the shock body

Zo.... How do you work with this?
The lower shock bolt mounting area on the control arm needs to be cut 25 mm. There is plenty of thread left in the insert, fortunately. That helps but does not solve the complete shock angle problem

Cut the dust cover of the shock so it just encapsulates the rubber bumpers located on the shock. Why? the full length covers will be pushed against the shock body and rub through over time. The upper round rubber mounting parts help take up the difference in angle between the shock and chassis mount holes

Fold over the edge of the heat exchanger where you see the shock touching them. You should place the car on ramps so the suspension is loaded. This will show you where they might rub

Mounting bolts will have to shorter for the bottom eyelet. You can cut down the stock 72-89 bolts, but take care to make sure you have full engagement of the threaded insert and bolt threads so the shocks are not left loose