Smiths Tacho information needed

[crbtogo]

I own a smiths tacho no RVI 5000/OOB. It is new but old and i have lost the instructions, i want to fit it to my v8 mustang and the wireing is proveing a problem, i know it is possible for it to be for a 8cyl but the configuration of wireing without info is not apparent. the wires on it are:-
Two white.
One green.
one red+white dash {internal light}.
One red.
one black.
Any help would be appreciated.

Colin.