I've just taken the standard rover head unit out of my car (R770) and need help installing my new alpine 7873r. (mk3 dash)

i,ve managed to connect the speaker iso to my new alpine iso - so thats fine.
And i understand that the skinny iso (one with the clock display and steering remote) won't work any more, so im going to forget that.
But i dont no what all of the wires are on the power iso. i gather that they must be the; power,ground, ignition etc. i need a wire diagram!
Also my new alpine head unit has another iso (with the igniton and power anteni on it) but thats it. All of the other wires are on there own. So i am going to buy a conecter that i can plug all of the free wires into and will convert it to an iso plug. This way i can then plug this into the old iso without having to cut up wires!

cheers (does anyone have or nowhere i can get a R770 wiring diagram from?)

Try and get hold of a converter rather than hacking into your loom. I don't know the mark 3 loom colours but the alpine ones will probably be red for 12V ignition, Yellow 12v permanent, black ground, orange dimmer (lights),, but it will probably say in the headunit manual. ISO connectors are just that, standard, so you need a converter that will turn a MK3 loom into a ISO connector. Autoleads do a number of these connectors available through places like Halfords or your local In-Car dealers.