Steering coupler

[68GMCCustom]

What size coupler was used on these trucks for the steering gearbox shaft rag joint? 13/16ths? And...where to get one quick?

My truck (w/'72 chassis) had an '80's motor in it, along with the accessories and evidently the steering gearbox. I recently pulled that motor and replaced it with a '70's 0010 block based 383... and have found one issue after the other. 1st the 305 manifolds (a temp solution) wouldn't bolt up to the 350 heads so we had to weld up some old headers, then the power steering pump brackets wouldn't work so I substituted a '70 Camaro keyway style ps pump and brackets that were on hand...so then the press on ps pulley wouldn't work...and neither would the high pressure hose since it was the o-ring type hose and now I had a flange type pump. So, my steering gearbox leaked so I decided this was a good time to replace it...and found my old lower rag joint is evidently about 1/16" to small.



I was about to just say to heck with it and buy a new March setup... but I can't seem to scrounge up the cash.
So what do I need for my new '72 gearbox and where can I get one quick?

Thanks!