Lenny, that must be among the worst fenders to lengthen
with that "reveal" that get wider the farther back you go
In reality you have to reshape it from front to rear
I did a-66 "streetrace" Nova once, i moved the wheel
opening forward to the bumper and made it longer. Novas
have real small openings. That way i don't had to
lengthen the fender that much, but a much easier fender
to lengthen
In the rear i made a new fender below the
"bead" with a longer higher opening but same shape as
the stock one to make the car so stock appearing as possible
And when i was finished with the bodywork his wife/ girlfriend or whatewer
said it had cost to much so he had to sell it
So i never saw it finished