Bulkhead Modification

Jack DeRyke’s January 2006 newsletter article on Cutting the Bubble Loose inspired me to action. Phyllis has endured the pain of riding beside me for the last five years. The bolted Recaro seat give her ample legroom but it doesn’t have enough room to allow the use of the backrest’s adjustable rake because of the bubble. This very upright position causes an extremely uncomfortable ride with the tightly sprung setting I use on my springs.

Some have notched the seatbacks for more legroom than DeTomaso provided while some have gone to a flat bulkhead design. I decided a notched steel door for the needed space in the passenger compartment was best for me. What follows is how I modified to my ’73.

Begin by doing a trial fit to establish the amount of depth you wish. Remember don’t get greedy here. I needed only 1½ inches. Remove the bulkhead cover and the steel door as outlined in Jack’s article. Mark the area of the notch you wish on the steel door. Be sure to locate the centerline of the alternator on the door too. Imagine the creases needed for the notch then mark these as well for reference. These, for me, translate to 8” down from the top corner for the centerline, 3” high from the base as a horizontal plane when the door is on the ground, and a 5” arc to the apex.

It is extremely important to test fit the alternator position many times. Measure the intrusion of the alternator blades and its pulley. The curvature here must begin over the blades and extend over the pulley. The lower section along with the belt need not be measured because no alterations are made in these areas.

The sound insulation is cut and a putty knife makes its removal easy. Mark the cut lines by transferring them from the padding. Mine was adjusted to 1¾” depth. Relief cuts eases the hammer work to form the notch. Tack weld then test fit to make sure you have the clearance you seek. Run the engine with the door in place to make certain nothing touches it. Complete the welding, paint and retest the fit. Glue the padding back and test again.

Next the leatherette is carefully lifted from both the fiberglass bubble and the flat panels flanking it by removing the metal strip and the staples holding the upholstery. Cut only the area of the bubble itself. Keep the flat piece on the bottom to hold the fiberglass cover tightly behind the console (optional). Save the bubble for a salad bowl or just discard it. The purist can cut and reform it to follow the notched door but it reduces the amount of space saved by at least ½”. Reposition the metal stay strips and glue back the flat side panels. Bolt the steel door then place upholstery batting on it. Mount the modified fiberglass cover in the car. Check to be sure that no batting shows.

An additional inch is available by moving the alternator back as outlined in Jack’s article but I made my modification on the lowest possible buck method. (I once took a Cost Accounting class years ago.) Forego the door pad to gain another 5/8” if needed.

Results are I gained about 2 inches for the seatback, but, more importantly, a happy wife. Note that it looks normal but it is very lightly padded and gives in easily when touched…the bulkhead cover, not my wife.

Rod Kunishige  May 30, 2006
Pictures added May 8, 2017