i need to buy a new wiring harness, who makes the most complete and best quality harness for a 1948 f1, any help would be much appreciated

 

There is at least one major and several minor concerns you need to resolve first. The major: Do you intend to stay with a 6 volt system? There is a big difference in the actual wires between a 6 volt harness and a 12 volt harness. The 12 volt is smaller wire and will not long handle the current.
The minors: What kind of amperage are you going to push? How many accessories, (circuits), do you intend to operate? What is currently mechanical that you intend to convert to electric, (sample/wiper motor)? Will you need any special connectors or extreme lengths of wire? I'm sure there are others, but this will get you started. There are several 12 volt conversion kits available.
I bought one like this. 14 Circuit Ford Wire Harness - KwikWire.com | Electrify Your Ride It's actually much more than I will ever need.
MAC's, Dennis Carpenter, Mid Fifty and others have replacement circuits and complete kits in both 6 and 12 volt versions.

 

Denny hit most of the key questions. In addition if staying 6V, are you restoring to stock or doing a restomod? Keep in mind, that you'll want to decide on your turn signal solution - dual filament bulbs or separate lights - before you get started.

 

I bought the OEM style one that Dennis Carpenter makes. Yes, it is more expensive, but it's completely cut, crimped, labeled and ready to go. You can install the whole thing in just a few hours.