Chevrolet had his own Hood Tachometer program, in addition also the products from DIXCO was as aftermarket add-on available.

In late 69, DIXCO had some advertisings in place which show a Corvette Stingray and a Chevelle SS with a Hood Tachometer installed.
 

On the big advertising a Chevelle SS and a Corvette Stingray was part of the vehicles presented with installed DIXCO Hood Mounted Tachometer. The 3rd Car is a 69' Dodge Charger

During my collection years I found DIXCO Hood Tachometers with the Chevy, Pontiac and Bonneville logo on the front plate: