I am going to get up on the soap box again.
If a 5/16 line would do the job for the high horse power engines, the Detroit bean counters would never have allowed 3/8 lines and fuel pumps to be installed on the high performance cars. Saving a dime on each unit, when you are talking thousands of units, is more important than adding bells and whistles.
Use the 3/8 lines and fuel pump, and sleep good.
