Anyone replace the speedo cable?, What am I not getting? Options

[tygaboy]

I'm working on my '74 1.8 and among other things, the speedo cable housing was cracked at the angle drive so I ordered a new one from Pelican.

I go to replace it by cutting the damaged end off and pulling the cable into the cabin.
I haven't yet disconnected the other end from the speedo. I figured I'd do all the dirty work under the car first.

As I go to feed the new cable from under the car into the interior, the end that connects to the speedo won't fit through the opening in the firewall - it's too big.

The end that connects to the trans is even bigger. The Hayes manual is no help. Not even a picture.

NOTE: I purchased the cheap GEMO product vs OEM.

Later today I hope to pull the speedo end and see if it's smaller but has anyone had this same issue or am I missing something simple here...? (IMG:style_emoticons/default/WTF.gif)

I'll also call Pelican and see if they can help.

Thanks,
Chris