How is it wired now? I assume keyed power turns it on. Could always just clean that connection up or run wires differently to make it look better.
As far as mounting can drill/tap into the frame for mounting points or find somewhere closer to tank to put it. Maybe an existing hole somewhere.
If...
find a new mechanic. Head gasket is somewhat easy to replace minus the machine/valve work on the head but a machine shop will do that.
What's his proof?
Primary is toward passenger and the other is a vacuum secondary, if you search around there's a lot of information on how to test if it's working or not. "paperclip test"
I only mentioned that fuel line getting clogged because it was happening on mine. Ended up pulling my tank and it was very...
Something could have gotten picked up in the gas tank side. Remove the inlet to the fuel pump and blow compressed air backward toward the tank to clear it out.
With fuel cap removed, you'll hear the air bubbles in the tank while doing it
They do have gaskets but all 3 i've gotten they've been coming off to some extent and not completely attached. I used super glue to re-attach and they've been fine since