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three quarter view of a simple graphic depiction of the truck scan in red on a white background

1. Here’s the scan of the whole truck before any modifications were made.

The Souza F-100 typoraphy

Part 2: Sectioning the Cowl

BY Ron CovellPhotography BY THE AUTHOR, Michael Christensen & Gary George


hile we often enjoy seeing adventurous experimentations with truck styling, this is something that is easily overdone. Sometimes the more subtle modifications produce a better result.

Last month we introduced Jason Souza’s F-100 project
being built at Gary’s Rods and Restorations in Northern California and showed the work done on the floor and firewall. This time we’re going to look at a subtle modification being done to lower the roof—not by chopping but by sectioning the cowl.

In preparation for the extensive body modifications being planned, Gary had the entire truck digitally scanned. This resulted in a complete surface model, so the body modifications could be tried out, tweaked, and visualized on a computer from all angles before any metal was cut. Gary’s neighbor, Sean Sinnott of DG Collective, was called on to do the scanning and computer modeling.

One of the first major body modifications was sectioning the cowl. While it’s common to chop the top on a custom truck, Souza, the truck’s owner, was very impressed with Chip Foose’s personal F-100 project where the greenhouse area of the cab was left intact and the roof was lowered by sectioning the cowl. This is a “sneaky” way to lower the profile of the truck, but the modification doesn’t call a lot of attention to itself. Most people appreciate the improved look without recognizing exactly how it was accomplished. Souza knew from the start that he wanted to incorporate this feature on his truck, and Gary and his crew were eager to work out the details required for the execution.

One of the beauties of working with a surface model on a computer is being able to quickly make changes to shapes and view them from any angle. After a lot of experimentation, Gary decided that sectioning the cowl 1 1/4 inches in front and 1 inch in back would produce the desired effect.

The first step was bracing the cab with tubing so it would retain its shape when the roof was removed. The windshield area on the roof was reinforced, too. The location of the cuts was carefully plotted, striving to provide access to the back side of the welded joints so they could be worked to perfection. The cowl was split from the roof just below the channel for the windshield weatherstrip.

The roof was removed from the cab and a 1-inch strip was cut from the rear cab panel. This portion of the cab is essentially flat, so very little reshaping was required, but welding and smoothing flat panels is a tricky operation. Emilio Belmonte, Gary’s metalworking expert, did a beautiful job with these modifications. A section was removed from the doorjambs; these were a little more challenging to align because of their taper.

The roof was repositioned in its new location with the front edge lowered 1 1/4 inch. Everything was checked and adjusted as necessary and the joints were carefully tack welded together. The cowl required the most extensive modifications. The sides of the cowl were removed, then the front edges were extended and the back edges were trimmed. The cowl vent was removed and new metal was shaped to fill the void.

The door tops were removed, then re-fitted in their new, lower position, ensuring the gaps were uniform. A section of the inner doorframe was removed to provide access to the weld on the outer skin, allowing the joint to be worked with a hammer and dolly and metalfinished.

Once all the joints were adjusted and the fits were verified, the panels were tacked, finish welded, and metalfinished.

The accompanying photos show the work in detail, and you can look forward to a series of articles covering the extensive body modifications in store for this outstanding truck, including a completely scratch-built bed!

three quarter view of a simple graphic depiction of the truck scan in red on a white background; a grey divider marking the cut line on the cowl
2. Lots of care was used to plot where the cuts would be made on the cowl. A curved slice was removed that was 1 1/4 inches high at the front and 1 inch at the rear.
three quarter view of the Souza's F100, with a focus on the height of the lip below the windshield
3. Note the height of the lip below the windshield here and compare it with the end result.
view inside the truck cabin with clamps and tubing for bracing
4. The cowl is cut here and the roof has been dropped down 1 1/4 inches. Note how everything is braced with tubing to keep it from changing shape.
close up of the stout plug welds in the inner structure
5. The rear of the roof is dropped down 1 inch inside the flat cab back and stout plug welds are made to the inner structure, maintaining the strength in the ’jamb area.
close view of an A-pillar
6. The A-pillars are reinforced in the ’jamb area, too.
wearing protective gear, the mechanic carfully welds the roof to the back of the cab
7. After trimming the overlapped panels to achieve a tight butt joint, the roof is carefully welded to the back of the cab.
view of the required vertical cut along the edge of the 'jamb
8. A vertical cut was required at the edge of the ’jamb to maintain the fit of the panels.
view of the welded and metalfinished 'jamb
9. A filler piece was carefully fitted and tacked, then welded and metalfinished.
view of the long welded joint on the back of the cab
10. The long welded joint on the back of the cab required special attention to keep everything straight.
the cowl corners are re-fitted and held in place by clamps
11. The corners of the cowl were removed then slid back and re-fitted to the lower windshield channel.
view of one of the cowl corners sitting on a table with a strip of metal clamped to its front
12. Next, a strip of metal was added to the front of the cowl corners.
the mechanic uses a planishing hammer to smooth the weld on the joint
13. A planishing hammer was used to smooth the weld on this joint.
the mechanic welds the cowl corners back into place
14. The lengthened cowl corners were then welded back into place.
new metals sit in the place where the cowl vent once was
15. New metal was shaped to fill the gap left when the cowl vent was removed.
angled view of the re-shaped cowl, completely welded and metalfinished
16. Here is the re-shaped cowl, completely welded and metalfinished.
clamps sit along the bottom of one of the truck doors
17. The door tops were re-aligned in the lowered roof, the bottom edges were trimmed, and they were tack welded into place.
view of the inner doorframe with the section just below the window removed
18. A section of the inner doorframe was removed to provide access for metalfinishing the weld on the outer doorskin.
outside view of the truck door after the weld has been smoothed
19. Here’s the door after the weld has been smoothed.
three quarter view from the passenger side of the newly sectioned cowl
20. And this is how the cab looks with the sectioned cowl. It’s a subtle change, but it certainly improves the look of the truck.
Gary’s Rods & Restorations
(831) 728-7025
Sean Sinnott DG Collective
(831) 464-8088