Hey Gary!
Yes, it's mechanical
....hey, it's a Cobra (replica)....we don't use that modern electrical stuff on gauges.
Yes, the gauge is decades old, and exactly as used on FIA cars.
If it's ever actually connected up (the gauge), my engine will need to be carb'd, not EFI....which I hope to be able to do eventually (carb fueled) if our SA club is successful in it's negotiations with the state rego boys.
....and if so, no, for safety, the fuel will not go any further south than the firewall, so should be quite safe enough to satisfy my compliance engineer, as well as me
Cheers,
Glen