Upgrading to 3/8 fuel line

I will stay with the 5/16" fuel line. A Hemi or dual quad big block may need a 3/8" line but probably not a 360. Would the existing vapor vent system work well enough to allow fuel to flow to the fuel pump and adjust for expansion in the fuel tank if I just cover the end of the vapor line (that originally went to the s6 breather cap) with screen to allow air movement in that line? Thanks for your replies.