As 3B posted, 1954 67xx trucks had a standard 235 engine and optional 261 engine (high-pressure engines with the "high-mounted" water pump).

here are locations of engine codes

If you have a 261 block and it is rebuildable, you might want to use it (a later higher-compression 235 head can be used/adapted). Or, post the block for sale/free in the Swap Meet.