This shows the u-joint arrangement for 54 trucks. The top pic is 3100 with torque tube, the bottom is 3600 and larger.
http://chevy.oldcarmanualproject.com/chevyresto/54137.htm

Here's the 53 and earlier. It shows the torque tube setup for the 3100. The 3600 & 3700 just have a front torque tube. Then the 3800 and larger are open drive lines.
http://chevy.oldcarmanualproject.com/chevyresto/53137.htm

The 3 speed and 4 speed, SM 420, were options for the the 3100 and 3600 trucks. The SM 420 was only offered in the 3800 and larger trucks. So, finding a 3600 with 3 speed is whats needed, along with an open driveshaft rearend, which there are many options out there.



1954 3600 Chevy Truck
"The Fake Truck"
In the Stovebolt Gallery
More pix on Photobucket