The "oddball" 1953 block that the 848 head does not fit is 3701946.
That block had a mechanical cam, in both cars & trucks, and both with head 3701887.
They tried 3 differents crankshafts in that block
until they came out with the later 53 blocks.
I don't think trucks had a later 53 block, just cars..
From then on, all 235 & 261 blocks had the same crankshaft 3701488.
