Many thanks for your responses.
@Tod - if all else fails, atleast now I know that one can be adapted to fit.
@plymouthcranbrook - I'm in England, so I'm gonna try and source what I need here first, but thanks for the details.
@Merle - Hey there, fella! Hope all's well. Thanks for the Roberts link.
I've got suspicions about this unit I'm after. When they originally customised the truck, a '70 Camaro was used as the donor car. I'm wondering if they used the Camaro tank & sender...
I'll get some pics up & hopefully you guys could confirm, because frankly, I don't know what the bloody hell I'm looking at.