OK I have not been on here for quite a while since I got my old 61 GMC going but I have driven it quite a bit. right now I volunteered to swap a friend's 62 chevy 1/2 ton over to power steering. like a fool I assumed he had the correct steering box. that was probably my first mistake. I just removed the pitman arm from his original box and find the shaft measures about 1.085" where the shaft on the power steering box he brought me measures 1.240" and he has no idea what it came off of. all I have from it other than telling by looks it's a GM unit is the casting has the numbers 7802644 on I as well as a 13 below that. I can also tell that if I could find a correct pitman arm to match it to the pickup steering linkage I will also need to shorten the steering shaft from the column.that I could handle but is there anyone that might be able to tell me what the box is off of or what might help? Raymond