White lines are relief cuts needed to allow the trunk lid to open enough. Only do this cutting once the entire trunk is laid up and in filler. New closed-cell house weather-stripping around the sealing edge will ensure watertightness.

The illustrated curved line is the neatest part of my convertible conversion.

This is a 2” cut out of the strut tower and the strut housing. Lowering the strut tower will allow the top to lay flat in the top well and make the top flush with the trunk lid. To cut the tower, carefully measure 2” down from the top of the tower, then torch cut at the 2” line and at the shoulder. Keep the top part parallel when welding it back on! It helps to make a 90-degree reference line down the center of the sheet metal so you can ensure a square tower when rewelding. The front strut inserts fit in the rear after removing 2” from the tower and housing. You may ship the housing to me for cutting if local fabrication support is not available.

Do not attempt to use the pattern I sent to lay out the top cavity. You need to transfer this pattern to cardboard.

All the cars in the last part of this video have the early trunk shape. The trunk is too long for the top to lay flat. The construction video shows my new, correct way to lay up the trunk. Tape the template to the car as described, and the top opening will be the correct dimensions. As you can see from the above shot, the leading edge of the trunk is well in front of the strut tower. Your trunk will be behind the tower. Cutting down the strut tower can be done after the trunk is complete. This step is not necessary if you will not be installing a top. A tonneau cover can be constructed by an upholstery shop to protect the interior. I split the tonneau with a zipper so the driver’s side could be open while driving. The post and Lift-A-Dot tonneau snaps, as used on British cars, work great. Install the posts on the metal defroster panel at the base of the windshield. I also installed snaps on the side window wipe metal pieces. They are stainless steel, as is the window surround.

The stainless steel window surround where it meets the windshield post must be left in place. Removing it will not allow the side windows to push in far enough to seal. Another trick is to use a second roller to push in the window. These rollers are spring-loaded and install under the window wiper metal (where your snaps are for the tonneau). Install the second roller before drilling for snaps! There is a left and right roller, so make sure you order both sides.

The trunk release I use is the entire system from a 280ZX. I weld closed the stock hole in the hatch, then weld a plate to the trunk between the taillights. Close the trunk, crawl inside, and position the ZX latch and U-shaped post. Mark with a pen, then bolt everything in. This is not a lesson on basic fabrication, only a helpful tip.

The bulkhead between the trunk and the cockpit is best made with a piece of thin sheet metal. Simply curve it around the perimeter, behind the strut towers. I put a 90-degree bend at the bottom to make everything look neat. Stereo buffs can use plywood instead to support big woofers.

A rear strut brace is not needed on this convertible because the metal you laid over the strut tower is a box section. This box section used to be the top hoop that the dome light went in—very rigid!

One of the final steps is to fill in the metalworking with “Bondo.” Please bear with me as I dispel some myths about plastic filler. Old timers may cringe, but here it goes! The new plastic fillers are composed of space-age polymers that are very lightweight. Also, the adhesives used are very aggressive. This means you can get away with disgustingly thick fills, with no fear of cracking. However, the base metal needs to be roughed up with 24-36 grit grinding, and the surface must not be able to flex. Now that I’ve explained myself, go out and buy a gallon of the best filler you can find at a professional automotive paint store. If you spent $12, you bought the wrong stuff. My favorite is by Evercoat. Pick up a box of 80-grit longboard paper and a longboard sanding stick. Rough up the trunk and area with the 36-grit, then pour on the filler. Cover the entire trunk with a thin layer, then sand it off with the longboard. Sounds like work? It is! But it goes a lot faster than filling in sections. The idea is that the 18” longboard will smooth huge areas in minimal time. The finished product will be smooth and straight. Since nobody makes 220-grit longboard wet/dry paper, you need to get it razor straight now with the longboard. This is not a lesson in basic bodywork, so I’m done talking about that.