63 LeMans, 4cyl 1bbl Fuel Line Diameter
 

The fuel line diameter in this year and engine combination is 5/16" OD.

Weigh in if there are other diameters for different configurations

Sounds right. 3/8 was used on the later V8 cars.
The 4yl used the small body fuel pump.

Any idea what delco fuel filter would have been used, which had 5/16?
I assume the factory jobber would have been painted blue?