The black lined area is where yo will add you pre-made fiberglass. Place it under the body & between the braces. Screw it in through the top of the body. Then seal off the area ( so the resin will NOT leak through ) underneath with duct tape. The resin will NOT stick to the duct tape , you can remove the duct tape you fiber glassing job sets up.
The top horizontal 2x4 tucks under the dashboard. The top of the 2x4 is the future top edge of the body. Get some 1/16" thick plastic ( can be cut with a pair of scissors ). The plastic should be cut in 3" wide strips. Measure from top of door edge to bottom of door edge. This measurement will be the length of your 3" wide strips. You'll need 2 strips. Make the fiberglass panel ( using 2 layers of 1 1/2 oz. fiberglass mat ) large enough to fill the door gap ( 2''s longer than the door gap ). The fiberglass panel will be trimmed to fit. Also make the panel 2"s taller then the door gap ) also to be trimmed to fit. Use a piece of cardboard to get the contour of the body at the door gap. Make the cardboard protrude past the body's outer surface. using a sharpie hold the sharpie against the outer body edge while you draw a line on the cardboard. Now you have a template ( pattern) to be transferred to your future vertical 2x4 ribs. Test fit the cardboard template's to fit both your front & rear door openings. If it fits the 2 different areas , then you can use your template for both of the vertical 2x4 ribs. Attach the 2 vertical to the underside of your horizontal 2x4 . I don't know where you would attach the bottom of the vertical ribs , that area is hidden by your floor .When your fiberglass panel is set up , tape it in place. Now on the inside of the body use a sharpie & draw a line at both door opening gaps. Wax one side of your 3" strips ( about 3 coats ) . Wipe off each coat before applying the next coat ( that will make 3 coats & 3 wipes ) . Attach your 2 3" strips to the outer edge of your fiberglass panel ( with short screws ). Make you plastic strip overlap your panel by 1 1/2"s . Scour the side of your panel that was against the wax ( when you were laying it up ) All the wax residue has to be removed .Tape your fiberglass panel back in place. Now screw the 3" plastic strip overlap to your body. Now cut 6 3' wide strips of 2oz. fiberglass. Cut them to fit the entire length of the crack between the fiberglass panel & the the door opening's edge. Now cut out 12 more 3" wide strips to glass in the 2 vertical ribs to the inside of your fiberglass panel. Now for your bare horizontal 2x4. Lay some duct tape along the top of the horizontal 2x4 ( One layer only ). Remember the excess fiberglass you trimmed away from you fiberglass panel ? One of the strips will be used to make the top lip which your body already has at each end of your door openings. This will continue that lip across the horizontal 2x4. At this stage of completion , your fiberglass panels will be too thin. Measure the space between your back door opening edge to the first vertical rib ( cut out 2 2oz. pieces of fiberglass mat to fit in this area ).Now measure the space between rib # 1 & rib # 2 ( cut out 2 2oz. pieces of fiberglass mat to fir in this area ). Now measure the space between rib # 2 & the front door opening edge ( cut out 2 2oz. pieces of fiberglass mat to fit in this area. Glass all of these fiberglass mat pieces into place. YOU ARE FINISHED !!Lol... come to Ohio!
