Block and Tackle replacment part

Thanks for posting. I believe this is either a S380-24 or S385-24 Channel Balance. The only difference between these two balances is the depth of the bottom nylon shoe, or the 'heel-to-toe' measurement. See the diagram below for reference. Compare both with your old balance to see what matches best. For a new stamp option choose 2340.

Comparison of the S380 and S385 balance shoes.