When I extended the rear wheel openings on my 65, I choose to NOT put the trunk extensions back in. I feel this is where all the moisture sits and then you know what happens next! RUST!. So I simply made braces out of round rod at the front & rear of the quarter panel where the trunk extensions would have been used for support. I heated the round rod on the ends and forged a "flat" then drilled and taped the ends for 1/4 X 20 bolts. Bent the ends to pick up the angles necessary for the frame and quarter panel. Much like the Dodge pick-up trucks do for their support. So now I can paint and keep the inside of the quarter panel very clean and most of all DRY! Just a suggestion before you "seal up" an area which is prone to rust!