I have a '56 GMC 100 and have rewired the entire truck. In doing so I removed the ammeter and replaced it with a voltmeter. In my research I came to understand that an ammeter was the cause of many a truck fire and their phasing out was a necessity. I was uncomfortable with the fusible link as a solution because I also did not feel confident about sizing, location and effectiveness. I also read that a voltmeter provides more pertinent information than an ammeter. One thing I recall is that the fusible link should be as close to the battery as possible, in fact there are numerous fuses which clamp to a battery post. Do more research on the effectiveness and necessity of the ammeter and if you really feel you need it instead of swapping it for a voltmeter then consult an expert in automotive electrical. It could save your truck. One last thing, because I did experience an electrical fire in my engine compartment (due to a mistake I made) I found it very important to install a cut-off switch. My immediate solution was a quick removal battery connection however, realizing that a fire could occur while driving, I decided to install a cut-off switch in the cab so I don't have to try to get the hood open and remove a battery cable if a fire occurs. Additionally, I purchased a Halon (clean-agent) extinguisher because the traditional extinguisher I used left a tremendous amount of residue and clean up was difficult.
