Do a search here for the conversion. I know there is a truck rag joint that works. I bought the Lee Manufacturing kit to install mine, works great.

 

Dorman part number 31011. it is sold under the "Help!" product line and is available anywhere they sell auto parts. i got mine from a locally owned parts store for a little bit under $70 to put the Monte SS box in my 74 Monte. the only issue i had was that the small and big bolts had to be flipped side for side and drill out the small hole in the metal retainer piece to keep my steering wheel pointing right side up.

 

The following flexible couplings will bolt right up to the Jeep GC power gear:

1977 thru 1982 Chevrolet and GMC C/K (2 and 4 wheel drive) pickup trucks
1977 and 1978 Camaro, Firebird, and Nova
1979 Nova
1983 thru 1986 Chevrolet and GMC C (2 wheel drive only) pickup trucks

GM part #7826542
JIML82

 

and that crosses over to Dorman 31011- i bet the GM part is even the exact same part but with a GM label on the box, since Dorman is an OEM supplier and what not.
once that is figured out, it's time to do the lines. i used lines for an 80 Camaro on my car and switched the pressure port on the back of the pump to a later model metric fitting.
i got the box for free from a car i parted out, and had about $90 into the ragjoint, lines, and fluid.