3.90:1 for 1/2 ton GMC & Chevrolet Hydra-Matic (not Hydro).
4.57:1 for 3/4 ton on both, I think.

Is the rear of your Hydra-Matic made for an open drive-shaft (exposed u-joint) or for an enclosed drive-shaft (enclosed u-joint)?

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.