1. Old Anvil Speed Shop started one of their recent complete builds with an original red-on-red 1962 Chevrolet Impala SS convertible.

By Ron Ceridono Photography by Taylor Kempkes

hen 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.

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.

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.

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.

To provide the solid foundation needed for the 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. 

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.

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.

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.

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.

2. The original GM frame was scrapped for a new perimeter frame designed by Paul Bosserman and built in-house at Old Anvil.

4. 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.

6. Passages for the exhaust system were included in the center crossmember as there wouldn’t be room for pipes above or below.

8. Designed to be both strong and light, the front crossmember provides wide, rigid attachment points for the lower control arms.

10. Old Anvil’s lower control arms use Delrin bushings for stability and vibration isolation. QA1 provided the 1-inch-longer AFX lower ball joints.

12. A little detail: the Old Anvil logo is included in the upper control arm bracket.

14. The frontend has 6 degrees of caster built in for straight-line stability. The power rack-and-pinion are from Detroit Speed & Engineering.

17. While the four-bar/airbag bracket appears to hang low, it won’t be a problem with 24-inch wheels.

18. Here, the rear four-bars are in place. The 9-inch rear axle housing is from Strange.

20. Paul prefers to use a low-mounted Panhard bar with a Heim joint at one end and a Delrin bushing on the other rather than a Watts link.

22. Of course raising the engine also meant the transmission would sit higher in the chassis.

23. The unique transmission mount attaches to the bottom of the frame; it’s designed to position the transmission pan out of harm’s way above the bottom of the ’rails.

25. Old Anvil’s Brandon Gerringer fabricated the driveline’s custom center support, which is necessary for the two-piece driveshaft.

26. Like we said, the Impala can get down on the ground. When it rolls it will be on massive 265/30R21 tires up front with 355/25R24s in the rear.