Gasline size.
 

Is there a preferred gas line size fuel pump to tank? Fitting to tank is 1/2" Fitting to Fuel pump is 9/16"'

Re: Gasline size.
 

5/16 is the size used on most cars. I don't know what the stock size was for your car, maybe a 1/4. Check the fitting - it may be an inverted flare

High performance engines used 3/8 or bigger.