driveshaft length rear diff swap

Have a 72 dart swinger went from 7.25 to 8.25 a body rear dont know what to do for driveshaft length difference di i cut it if so how much . Does anyone know of a good place to have this work done in san diego area. Or does anyone have a driveshaft that will fit for sale (cheap)in my area. My place of work is moving and are cutting hours due to the move money is tight.
I need to start driving to work asap. My carpool ride no longer will take me to work. All help is appreciated