Replacement Fuel Tank Question

Now if it was me. I would replace the piece in the trunk with the 68 up type from a donor. That will get you 2 straps routed forward to rear rather than the single left to right that 67 has.
It is a good bit more work. You would need to cut the 2 'T' shaped notches for the forward end of the straps under the car. Advantage is you or anyone else can add dual exhaust without working around the 67 strap. I'll also mention the safety factor that contributed to the change in design.