My '39 has returnless. Originally the 5.3 motor had a supply and return with the regulator on the return side of the injector manifold. To clean things up and eliminate lots of piping I installed a Corvette filter/regulator back near the tank. Cost was $47. Not an in-tank unit but does cut down on piping. As a side note I used the nylon fuel lines that all the newer vehicles have. While at the local junkyard fill your pockets with the quick disconnect fittings. They work great and never have had one leak. Only down side is it's necessary to have a tool to push the nylon over the fitting. Lots of videos on line regarding making your own tool. Another side note is to make your own in-tank pump module. There are several pumps for just over $100 (avoid off-shore knockoffs) and a good picture on how simple it is take a look at Tanks Inc.