Raptor,
Have you considered modifying repop 3/4 ton boards?
Get 2 sets of 3/4 ton boards, cut the front section off of 1 set and the rear section off the other set and weld the 2 sections together, thus coming up with 1 set of longer running boards.
As was stated before, the fenders, cab mounting, etc. are all the same, just the length is different. By using the above method, you will have the correct mounts front and rear with the longer boards you need with the proper profile already in them. You may want to reinforce them from below after welding.
I have a 3804 myself, but it's a '59. I'll be modifying my running boards to allow for my dually rear wheels.
Lane
