Here's a poor shot of my spare TB (2.1) which has about 90K miles and is
relatively tight. The orifice is uncovered by the plate on this one
(bottom).

https://picasaweb.google.com/lh/photo/SOZBHVEbVaS8cDgzVzC8JNMTjNZETYmyPJy0liipFm0?feat=directlink

I can check some more if you'd like.

Angus

On Wed, Jun 11, 2014 at 9:04 AM, Alistair Bell <albell@shaw.ca> wrote:

> The little vacuum port on the throttle body - I believe the orifice is
> covered by the throttle plate when throttle closed - am I right?
>
> I can't recall for sure. I'm picking up on a project where I rebushed
> (delrin), turned the throat out a few thous, and made a new plate.
>
> The TB currently on my van has become so worn that it is practically
> impossible to set the TB switch and have it work consistently.
>
> Thanks
>
> Alistair
>