If I remember correct, most of the Fomoco 4X4 axles around that year (maybe not all) had the tie rod in front of the axle and the steer box ahead of the axle with the drag link connecting the pitman to the tie rod instead of a sreering arm like a GM 4X4 axle or the stock '50 has. Might be a little tricky to use the stock steering box if that's the case. Are you going to be able to use a Fomoco T-case? The Fomoco axle has the diff offset to the left where GM axles and T-cases are offset to the right.

Joe McNeel

http://mcneelnet.com/~jmcneel/59.html