I don't know if this helps....
Some info. I could dig up on a Technovance valve guide... it looks like they are an importer/exporter. At one point looks like they had a website
www.wristpin.com but doesn't seem to work.
App: 1965-1992 Porsche 911
Brand: Technovance Valve Guide
Part#: W0133-1640220
Description: Standard - Phosphorous Bronze (9x13.05x52mm). Standard.
Availability: In Stock
Usually Delivers in 2 to 3 days
Engine-Fits
$6.95 each