Block casting number is 3835911. Attached are some pictures of the casting number on the front/right above the oil pan, and two pictures of the driver's side of the block.
This truck is also equipped with a 4-speed manual (1st gear is granny), so that has been changed as well. Still has a torque tube (enclosed driveshaft).
1948 Chevy 3100 Thriftmaster pickup Old skool engine swap ('54 pass 235) Four on the floor 12v conversion