What are the different block casting numbers to determine the engine size on a 63 truck

the engine size is on the lip of the block just be hind altenator if the block has never been machined although i did disassemble a 225 stamped block to fined it was a 198.

As terrylittlejohn said, the stamped number is right here,

unless the block has been machined. Between and below #1 and #2 plugs, beside the coil.

As I understand it, 198's and 225's use a common block. The cranks and rods make the difference. 170's have a different block.

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"When you find a big kettle of crazy, it's best not to stir it." - Pointy-haired Boss

1964 Valiant V200, 225/Pushbutton 904
BBD, CAI, HEI, LBP, AC, AM/FM/USB, EIEIO