Need a source for 1966 IMPERIAL upper and lower ball joints

I am looking for where/what to purchase the correct fitting Upper and Lower ball joints for my 1966 Imperial Crown Convert. Originals still in car but I am thinking of doing the upper and lower arm bushings and might as well do it all at the same time.
I have the bushings, but need the ball joints. NOTE: On Summit Racing site they list several different ones, so not sure which is correct.
Thanks
Author: watchfatha