74 malibu gas tank

[74chevelle]

I am trying to replace the gas tank on my 74 chevelle 2dr. The readily available replacements from Spectre and Dorman all have an updated filler neck that uses a modern plastic screw on gas cap instead of the original style. They insist it will fit but it interferes with the filler neck opening under the license plate. Even the replacement filler necks use the updated cap. I've made requests to all the sellers on the internet that I can find but most are just resellers of Spectre or dorman tanks. Is anyone aware of someone who makes a tank with the correct filler neck? At this point I will even consider a good used one that I can reseal.
Thanks, Alan