Need help on fuel tank to fuel pump hard line size for big block

[1963c-10]

Normally I'm in the 60-66 section, but need some input from the guys with factory big blocks in the 67-72 trucks.

Was the factory big block truck hard line from the tank to the fuel pumps 5/16" or 3/8"?
In the 1st gen c-10s it seems the 6cyl/and sb motors were 5/16". But chevy has a listing for a 3/8" line also.

I'm just wondering what line the big blocks had so I can get a 3/8" hard line if needed.

Just done with a big block conversion in my 63 and I want to make sure the fuel delivery is adequate to the fuel pump.

Thanks for any help in advance.