What is the purpose of the piece of cardboard between the firewall and gas tank on a 26 coupe. Is it necessary?
Cut down on wear due to metal to metal contact (Vibration). Silence is golden
If it wasn't necessary, Ford wouldn't have put it there. They were ruthless about cutting costs.
I tried the cardboard. It pushed the tank to far back. The tank would not position correctly for the primer/mixture rod to fit.
At the time I was willing to try just about anything to get the fuel tank to fit correctly.