If you can return the pump or exchange it another option is to use a 1952 or earlier pump with the 5/8 pulley and use your 216 balancer. Depending on your generator/alternator/voltage choice you may have to change the front pulley on that too. I went with a 216 balancer, 1952 pump with adapter like you have, and took the pulley off my 6 volt generator and put it on my 12 volt generator.
Chuck
