I have the hood tach installed on my 69 the wiring i got with it form first place auto has a grey connector that looks like it would go to the tach it self there is a pigtail coming out of the tach then there is a red connector with a single blade that i think goes to the distributor tach connection
there is a ground ( obvious)
then there is a fuse with a metal c clip on it not sure where that goes
I attached a photo