Ike - I'm trying to avoid any liability here!
Years ago, I seem to remember some british cars with copper or brass tubing to the gage. They always had a well supported section with several loops so that the movement in any given section was near zero.
Our current Smiths and S/W gages come with
plastic tubing, and I'm using a similar setup on my street car.
That said, at least use a length of -4 hose from the engine to firewall. It's cheap insurance.