I used to get stuff from Concours Parts, but they did me wrong on a replacement radiator so I quit using them altogether.
Have gotten stuff from Dennis Carpenter, Obsolete and Classic Auto Parts, Mac's (Ecklers) and a few others in the past that have gone out of business. My favorite of all time was Joblot Automotive in Queens Village, NY, surprisingly helpful and freindly service and very low prices, but sadly long gone now.
Most chain auto parts stores are useless except for NAPA, but sometimes you need to wait for them to ship in from another local store or from main warehouse. Better than waiting a week from mail order catalogs. Napa is good for ignition parts, oil, filters and usual maintenance stuff, but they most likely can't get water pumps, fuel pumps, carburators, starters, generators or any cosmetic stuff.
Not too many ways to get around the heavy shipping charges. Amazon offers free shipping on some stuff, but they are not known for antique auto parts sales.