You might consider changing your closed knuckle front axle to a later model dana 44 or a gm 10 bolt --that are already set up for disc- 73 up chevy k10 or k5. I used a gm 10 bolt from a full size 88 blazer on my 67 k10. I do not know if you will need to move the perches for a 64 --I did not on my 67.
I will guess you are running a 3.73 gear which is common on front axles with lockout hubs that have disc brakes. Or maybe you have 4.10's or other.
Last edited by 42465967; 07/10/2017 12:14 AM.