You can press down the fan hub and use a shorter pulley. Make sure you support the impeller end of the shaft, not the impeller itself, or you may ruin the pump. A WP pulley from a long pump SBC can be used, or a WP pulley off of a Ford six can be used.
Patricks sells a "kit" that is a shortened pump and pulley.
You could also buy an adapter plate that will alow you to use the '54 pump. It will require drilling and tapping two holes in the block. Reuse the '54 damper as well then.