DAVID98GT

I have a 98' gt and I swaped my piece of S**T t-45 for a 3650 and now my spedometer doesnt work because the t-45 is mechanical and the 3650 is electronic ( as u may already know). I've heard there is a new sensor to correct this, dont know if this is true or not. But if there is a sensor has anyone seen or heard of it? And it so where can I get one. If not does anyone know how to correct this problem? any help would be greatly appriciated, Thanks