Building a Custom Frame for a 1962 Chevy Impala Convertible

By Ron Ceridono – Photography by Taylor Kempkes

When a diehard 1962 Chevy fan wanted someone to build an Impala convertible unlike anything seen before, Old Anvil Speed Shop got the call. The task was to build a car that could drop to the ground one minute and carve corners the next, house 21- and 24-inch wheels, and handle 1,200 hp. Obviously the first step in this process was going to be building a one-of-a-kind chassis.

02 Custom 1962 Chevy frame with mounted performance wheels awaiting drivetrain assembly — The original GM frame was scrapped for a new perimeter frame designed by Paul Bosserman and built in-house at Old Anvil.

Paul and Jenna Bosserman started Old Anvil Speed Shop in Orange, California, in 2018, specializing in chassis engineering, fabrication, and sheetmetal work. Today, they manufacture their own CNC machined billet parts and custom wheels, and with their focus on complete custom builds, they’ve added facilities for bodywork, paint, and upholstery.

03 Body assembly of the 1962 Chevy convertible using a hoist with new quarter panels being fitted — A sign of things to come, a test-fit of the Nelson Racing Engine that’s good for 1,200 hp.

One of Old Anvil’s recent builds is based on a very original 1962 Impala SS convertible that had traveled a mere 42,000 miles in its lifetime. To meet the customer’s vision for the ragtop, it would have to be built from the bottom up, which meant an entirely new frame would be required.

04 Jig setup for welding chassis components for the 1962 Chevy convertible — The new rectangular tube frame has 3×4-inch, 3/16 wall main framerails with 2×4-inch inner and front ’rails. In the rear, the framerails were inset to accommodate the massive rear tires; those portions are made from a combination of 2×4- and 2×3-inch material.

First introduced by Cadillac in 1957, 1958-1964 Chevys had what was called a cruciform, or hourglass-shaped, frame. GM touted the design allowed the seating areas to be lowered, making for a lower roofline. Of course, the bean counters loved these frames for their cost-effectiveness. The same basic frame could be used under a variety of GM cars by simply changing the length of its centersection to change the wheelbase. However, the problem with these frames was a lack of torsional rigidity, so they relied on the sills of the body to add strength. All things considered, these frames were not a great foundation for performance suspensions.

05 Fabricators align custom chassis brackets for precise frame assembly — To get the Chevy to go as low as the owner wanted, a huge step in the rear framerails was needed, which would also require a new trunk floor and wheeltubs.

To provide the solid foundation needed for the Chevy modifications planned, Paul designed an entirely new perimeter frame, along with long-travel independent front and four-bar rear suspensions. Old Anvil’s Brandon Gerringer, Jake Caballero, and Phillip Avila handled fabrication.

06 Close up of tubular chassis reinforcement welds on the 1962 Chevy convertible — Passages for the exhaust system were included in the center crossmember as there wouldn’t be room for pipes above or below.

Both ends of the chassis are on airbags that allow for a total of 7 inches of suspension travel. Paul designed the suspension to enable the Chevy to come within inches of the ground and then rise to a reasonable ride height. The ride height and air pressure management system are from Air Lift Performance; ride quality will be assured by King Shocks, and sway bars on both ends from Old Anvil will keep the Chevy flat in the corners.

07 Welding a reinforcement plate onto the 1962 Chevy frame for added rigidity — To add strength, the center crossmember tubes are tied together, and openings in the plates ensure water and debris aren’t trapped.

With the stock chassis out of the way, the new frame, replacement floor, and body joined. The rocker boxes were welded to the sides of the main ’rails, and the rest of the floor was welded to the top of the ’rails. In addition, the rear crossmember of the body is welded to the ends of the framerails. The result was a unitized shell, allowing the suspension to work as it should.

08 Fabricated seat bracket with precision welds for secure interior mounting — Designed to be both strong and light, the front crossmember provides wide, rigid attachment points for the lower control arms.

The engine and transmission would also be special along with the custom-built chassis. Underhood, the original small-block 327 and BorgWarner four-speed will be replaced by a Nelson Racing Engines LS-based 427 backed by a 4L80E automatic transmission. Topped with a Kong intercooled supercharger, the engine is said to produce 1,200 hp.

09 Technician fabricating custom components for the convertible’s suspension on a jig — Precision fixtures are used to assemble the control arms; this is lower under construction.

While relatively new on the scene, Old Anvil Speed Shop has already gained a reputation for creativity and craftsmanship—their work on this radical ragtop is just one reason why.