I'm adding a frame mounted pre filter, and wondering which size ball valve to use. I'm planning to put a ball valve on the tank side of the filter. All the valves I've seen for our applications are labled 'Standard Port', meaning that the the liquid passage (hole in the ball) is one pipe size smaller than the pipe size. For example, a 1/2" ball valve has a bore equal to a 3/8" pipe. The Racor head I'm using takes 3/8" fittings. If I use a 3/8" ball valve, will I negativly affect fuel flow due to the 1/4" pipe bore in the ball of the valve? My other choice is to use a 1/2" ball valve. That will provide the same bore size in the ball as the other 3/8" fittings on the filter. The problem here is that I'll be using 1/2" to 3/8" adapter fittings, and I like to keep things as simple as possibe. I guess the third choice is to not use a ball valve at all, but from what I've read, its nice to have a valve to shut off fuel from the tank when changing filters. Any thoughts on fuel flow if I use the 3/8" valve (3/8 pipe fittings, 1/4" ball bore)? Thanks!