I've started the process of lengthening my fiberglass fenders. I've determined they need to be extended 4.5". 

My first task was to clean the fenders.  This yielded a surprise:  Business cards from the builder of the body were embeded into both fenders.  To the right a shot of one of them. The information suggests the seller was H.C. "Van" Wagner out of Puyallup, Washington.  He sold Custom fiberglass products including Bobcat products.  The name of the company has faded, but I have the address and phone info.

Once the fenders were cleaned, I cut them in half and I cut out the indent (traditionally for the battery) out of the passenger side.  Once they were cut, I tapered down the cut pieces.  To the left are the cut fenders.

The next step is to fiberglass them.  I'm going to try laying down a layer of gelcoat and then lay the fiberglass over the top of it.  I' haven't used gelcoat in my previous patching jobs, but am trying to gain experience so that I can use it when I do my custom hood project.