Technical Need help from you early steering box gurus

Got a buddy over here in NZ with a 34 Lincoln which is right hand drive, I think the steering box has just been a LHD box flipped as the worm gear is the same as a LHD worm. Ive posted the pics of it showing that its considerably bigger than its Ford version, which appears the same as the 37-48 Gemmer style internals. The sector varies from the Ford box though. Im trying to track down a replacement worm and sector, be it a new or good condition second hand one, is anyone able to shed some light on where I might find one, or if its out of anything else other than a Lincoln? I was thinking it may have been the same as a later model Ford truck because of its size.
Thanks in advance..

 

Maybe this will help some. Rod

http://www.fordgarage.com/pages/steeringshaftwormchart.htm

 

Thanks for that Rod, problem is the biggest the chart shows is a length of 3.5 inches for a truck or COE, the one im looking for is a monster, 4 inches in length. Anyone else got any ideas?..