Bango brass blocks are readily available at CarQuest in Canada same should apply for the USA..... about $20 each....available in single or Y shaped or as union blocks. Don't forget to buy the copper washer and the new special bolt (center core is drilled out to flow brake fluid) that attaches the brass block to the WC.
At todays' price for Brass blocks .....a scrounging visit to an old junk yard can be profitable.... I beleive Jimmy Carter also stocks them.
Bob
1940 Chev CMP