whats the difference between 2wd and 4wd steering box

[Sweet72]

These are the NAPA power steering gears for 1972 trucks I found on their website. According to them the 2wd and 4wd PS gears are different. The only difference I can see in the specs below is the # of turns lock to lock. I have a 1980 PS box from a 2WD on my '72, and it is real responsive and improved the steering greatly over the manual box. I am using a '72 PS pump and had to make a special high pressure line with the metric O-ring fittings on the gear box end. I'm sure someone on the board can give you a better answer to your question about the turn radius...Good luck, Sam.

4WD
part no. NSP277502
# of Mounting Holes:4
# of Turns Lock to Lock:3 1/3 - 4 1/4
Input Shaft Diameter:13/16"
Line Thread Size:11/16x18; 5/8x18
Output Shaft Diameter:1.25"
Type of Hose Ports:Tube Seat

2WD
part no. NSP277501
# of Mounting Holes:4
# of Turns Lock to Lock:3 1/3 - 4 1/8
Input Shaft Diameter:13/16"
Line Thread Size:11/16x18; 5/8x18
Output Shaft Diameter:1.25"
Type of Hose Ports:Tube Seat