Let's get back on topic here. Thanks.

My guess is someone replaced the original dual action fuel pump with a single function one. They then plumbed the wipers to the manifold and left the original line in place.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.