My preferred wiring harness companies are Ron Francis
https://www.ronfrancis.com/ and American Auto Wire
https://www.americanautowire.com/ I bought the Painless Performance harness for my 1940 Ford project. The unterminated wires were corroded under the insulation. I called the talking head in the customer disservice department and was assured that it was all my fault. The talking head never asked any questions. I think I may not have been the first customer with corrosion problems.
I have a few ongoing problems that come from the poor quality wiring and the Ford may have to be rewired. This will be a major event because the car has been upholstered. Many of the wires have been replaced, at my expense.
This will be a good opportunity for you to bring an ancient wiring design into the the modern age. If your truck is not a 12 volt system, make the change. You will never regret it.