I replaced my rusted tank a few years ago with one from obsolete parts in OKC. It is made in Canada. I had no problem with the mild 351 Windsor that was in it previously, but I had fuel starvation problems at higher rpm when I changed to the 408 Cleveland. So I began swapping out the old 5/16" fuel line for 3/8 and knew that I would also need to increase the in-tank pickup tube to 3/8". After pulling the tank I noticed that while the pickup tube itself is 5/16", it is swagged in at the tank fitting, and the actual I.D. at the fitting is 3/16". While this is probably adequate for a stock engine, or mild 302/351, it is not adequate for a higher horsepower application. I just wanted to pass this on in case someone is upsizing your fuel lines, be sure to check the I.D. at the tank as well.
James