Slant 6 coil

What voltage should be on positive side of coil when running ? & what voltage on leaving side of coil when running ?

my + side of coil to ground is 9.5 vrf
My - / leaving side going to my distributor is 5 vdc

ive bought 3 different tachs and non move the needle . I'm thinking that 5vdc to ground is not enough signal to move the tach I don't know though . All 3 tachs are different brands and are wired red to battery positive , black to negative , green to coil .


Only wiring under my hood to get idea on my rpms for timing sake I'll remove once dialed in . Why I disnt wire to ignition 12volts .