What is this? (gm part)

[raycow]

Those washer bottles were more common on the higher priced cars than on Chevys. They might have been standard equipment or maybe that class of cars was just more heavily optioned as a matter of practice.

Cadillac wasn't the only engine with a top-mounted fuel pump. The Ford flathead had one and it was infamous for being prone to vapor lock. I don't recall hearing those stories about the Cad though. Maybe GM engineering was better?

Ray