I don't believe Sun tach's were offered through GM on the 66 Chevy truck. I think only GMC's got those. I believe the factory tach that went in the Chevy cluster was probaby a Delco item, and I don't know if those used a transmitter. Here's an example of a replacement item: http://www.classicparts.com/1963-66-Tachometer-Conversion-Kit/productinfo/24-735/ Although back in 1966 Sun Tach's were a hot rodder's must have item. Many were installed in trucks right along with every brand of cars. My dad even put one in his 1958 Nash Metropolitan. If it was an aftermarket purchase, the transmitter would go wherever the owner preferred. This was normally on a fender panel or somewhere on the firewall. I would think the fenderwell would have been preferred as there isn't much firewall space available on a heater equipped truck.
Not sure if it is factory. It is in the gauge cluster. It is a Sun tach 8500 rpm. The transmitter is a EB-9A also made by Sun. I am thinking it needs to be on the drivers side fender well??? Any input would be helpful.
