BRAND NEW SOUTHWEST SPEED POWER STEERING CENTERLINK CONVERSION ON THESE 58-64 CHEVYS, IF THEY HAD THE ORIGINAL POWER STEERING, THERE IS A VALVE ON THE END OF THE DRAG LINK, WHICH HAS ALWAYS BEEN A PROBLEM. THEY NEVER WORKED PROPERLY AND KEPT YOU FROM SWITCHING TO A NEWER MODEL POWER STEERING BOX. THIS CONVERSION PIECE ENDS THAT PROBLEM. THIS SCREWS ON THE ORIGINAL DRAG LINK AND ALLOWS YOU TO USE A NEWER-STYLE POWER STEERING BOX, SUCH AS A 605 BOX. FITS: 1958-1964: CHEVY: IMPALA > BEL AIR > BISCAYNE > BROOKWOOD > EL CAMINO > KINGSWOOD > PARKWOOD > NOMAD > & SEDAN DELIVERY (WITH THE ORIGINAL POWER STEERING DRAG LINK) SPECS: THREADED END IS 1 1/16" X 16 FEMALE OVERALL LENGTH: 4 1/2" OVERALL HEIGHT FROM TOP OF STUD TO BOTTOM: 3" 1 7/8" O.D. AT THE THREADED END 1 3/8" O.D. AT THE OPPOSITE END