I am pro streeting my 67 GTO and will need to lengthen the wheel wells. What is the best way to do it. Is there a link to a site that explains it.

you meen to make the wheel base longer or just tubing the car out

i have done it a couple ways over the years-if the problem is in the front, you can cut like a pie shaped piece out, kind of radius to match the wheel well-i make the first cut along the edge where it bends inward, then the next cut toward the front as much as needed, then bend the edge i cut toward the new body line and weld it up(i know it might sound confusing)
another way i have done it is use an aftermarket patch panel, cut out a section of the old, cut the patch panel to match puus a little more to make it like a strech opening-on thing when you stuff a huge tire under it, there becomes a problem getting the tire off, sometimes you have to jack it way up, rem the shocks, lower the rear way down-my old 55 took about 45 mins. to remove the rear tires-lol

another way i have done it is use an aftermarket patch panel, cut out a section of the old, cut the patch panel to match puus a little more to make it like a strech opening

I have never done it myself, but I have seen it done in a similar way to what you describe:

Cut out a rectangular section around the whole wheel well to remove it completely. Cut it in half at the top, move the front piece forward and the rear piece back, as much as needed for clearance. Then cut a piece out of a patch panel to fill the gap at the top.

This was done on a 2nd gen Camaro, where the wheel wells have an almost straight and horizontal section at the top to begin with, so the scab piece from the patch panel fit pretty well. You may have to fab your own piece to fill the gap on a rounded wheel well like on your car.

Did this on a Super Bee.

Find the center of the opening and make a cut straight up the side of
the quarter panel, about 2" long. Scribe a line horizontal with the ground
at least as long as you need the wheel opening. Take a square and
square it with the horizontal reference line and draw a vertical line
down the quarter panel. Do the same on the other end.
Take your air saw and cut on the lines. Measure however much you
want to stretch the opening from each new cut. Divide the amount
equally so the opening is not off center from the rear axle.
Scribe two more vertical lines that distance behind each new cut, and cut
that out. Put the pieces of the quarter back in their perspecive places and
fill in the center. I like to butt the edges and weld.
This worked pretty well for us.

Thanks guys. Anyone know of a link with pics.