hello I have a 1968 firebird with a BBC 454 with HEI ignition. I have a hood tach thats not working at my tach thats in my instrument cluster autometer ulta light II is working but I tried to hook up my hood tach and its not working. I checked the voltage to it and I know i am getting voltage to the tach and the bulbs to the tach are working and i have a good ground i am wondering if there is a tach adapter that i can use to hook up my hood tachometer. in closing i use to have a BBC with a 402 with a MSD system digital 6 box and I had both tachometers working together in the instrument cluster and the hood tacometer.

You generally need a filter to use a MSD box with an OEM tach. Consult the MSD web site.

i dont have a msd digital 6 box anymore just a HEI msd distributor for my BBC

You will need to install a Pontiac engine in order for the tac to work...

Thanks, I wanted soooooooo badly to suggest that was the issue, but don't have my degree in Psyc yet.