tach question

i have a straight 6 with the tfi ignition system... im trying to find the correct location to hook in the tach..right now i have it hooked to this little conector coming off of the distributor.... it doesnt hook to nothing its just 2 wires coming into the little box thing.... i have it hooked to there right now and it does not seem accurate at all...there is no where to hook it to the coil that i can see and it doesnt say in the book where to connect it either.. thanks

i think you just hook it to the small terminal on the coil opposite the red power feed... i believe it acts as a negative and feeds your tach at the same time. i could easily be wrong tho...