You could actually test out the modification with two feet of twelve gauge wire with alligator clips on each end. Clip one gator end on the top post of the circuit breaker over by the starter solenoid and the other end on the passenger side clip of the #1 glass fuse. Then just drape the wire behind the engine so it's not in the way of anything (like maybe the throttle linkage). Then drive your car around for a weekend and see if you like the new behavior of the amp gauge.
