We have FINALLY got our sun tach boards where we want them. They replace all the guys of a typical sun tach box and eliminate the use of batteries. They also allow the choice of 4, 6, or 8 cyl and are able to be calibrated to your Sun tach head unit. They require very little work to install and from the outside, look completely original. They work on 6v or 12v. I have a temporary website up with our contact info, tomorrow I will have the instructions up for all the see. http://www.brantinghameng.com/BEI/ http://beiautomotive.mybigcommerce.com/ Direct link to store and where to purchase. Paypal ready. You can also order over the phone. 972-480-4263 Email: orders@beiautomotive.com $54.99 (board only, does not include the case)