Measuring front sway bar size?

Sounds simple, but??

I need to order new bushing for the front of my 65 911. I measured it and it is 13mm, the square ends are 17mm.
In the catologs they have 16mm, 19mm and 22mm??

So which ones do I get?

Thanks for any help..
Bruce

No stock bars from that early were 19 or 22mm, so you can rule those out.

Actually, just to confuse matters further, I am pretty sure the early bars are 15mm, even though the bushings are listed as 16mm!

You may want to call a tech guy at Pelican Parts or Stoddard to verify what you need...they can check the factory parts manual.