Yues, I did see the brass reducers.
But, in the case of brass fittings, they fit inside the hose, so you are further reducing flow of fuel.
I do believe that whatever is under the 1/2 inch hose at the end of the card tube will be the determining factor in what I have to do.
unless you have something that's pretty nasty, 5/16 is all you're gonna need on the street and 3/8 is what most track cars use. so, i wouldn't really be worried about flow, especially on a 318.