D.J.

Advanced AP here didn't have the blocks and couldn't even order them. Banjo block and connector block are the same thing.
I would bet the WC you got from ClassicParts.com is the correct one. I've dealt with them and they are very good, they also specialize in parts for older GM trucks.
The only supplier I've found that has the banjo blocks is Jim Carter. You can call their tech help line at 1-816-252-5857 to ask about parts.
Here is a link to a page from their online catalog showing the parts you need http://www.oldchevytrucks.biz/47_55/full.asp?page=83

Jim