55 - 57 can use a 605 gear box , you have to mate the upper 605 with a lower shaft from the 55 ,grind a couple of teeth off the shaft gear . you can buy a almost bolt on gear from classis chevy club 1 800 456 1957 ,you have to weld a bracket on the frame to hold the gear .



i prefer to use a rack , i think they drive alot better than a 605