Some torsion bars on ebay. I had to ask the seller what
they were since he didn't seem to know -6 and -4 are
different. The part numbers he gave me from AA are
the original 17.9mm 914-6 bars. So if you are really into
stock front suspension this could go cheap.
I was looking for a 21mm set for a -4 for a friend.

ebay 914-6 bars

Mark S.
'70 914-6

All 911's up until 1989 used the same bars. I have a set to give away if you want to send me a box.

B