Good/Bad Experiences when changing to 3/8" fuel line & sending unit?

Oh you posted mild cam, not stock 340.
That 340 I was running had a Comp cams 280H, and would run just under 14.0. Its best was 13.77 and 99.5 mph with 24" autocross tires and 3.23 rear.
Looks like I changed fuel line and pickup in '04. So those drag strip runs with the old 340 were with the 5/16 line and pickup.