I just checked Amazon.com, and there is a firm selling a complete factory service manual, which includes wiring diagrams, for 1951 thru 1954 L-series International trucks. It's a little pricey, about $70.00 with shipping, but since you have three trucks, it may not be a bad deal. Those older vehicles didn't have the complicated wiring that newer ones do. You could replace the wiring one piece at a time, if you can tell where it goes, OR, there is a company called Painless Performance,(www.painlessperformance.com.) that makes up wiring harness for many original and custom built vehicles. Likely would be a little pricey but one of their universal kits would probably do the job. Just a few thoughts, hope it may be a little help, and good luck on your project. Keep us posted.