Classic Truck Performance: Building a C10 Oval Exhaust With Granatelli Motor Sports Tubing

Classic Truck Performance's September 2024 issue ran "Room to Breathe Part 2: Rounding Out an Oval Exhaust," in which Ryan Manson built a full stainless exhaust for a 1964 Chevy C10 using Granatelli Motor Sports oval tubing. The story was posted online on October 15, 2024.

Why Oval Tubing

According to the article, the C10's modified chassis ruled out a bolt-on kit. The goals were stainless steel and enough flow for the LS engine to handle forced induction later, but full 3-inch round pipe would not route easily. After a conversation with Joey Granatelli, the build switched to Granatelli Motor Sports oval tubing, which the story says is made from 304 stainless and measures 2.2 x 3.45 inches outside.

The article's math puts a 2.5-inch round pipe just under 5 square inches of area and a 3-inch pipe a bit over 7. The oval comes in just under 6, which the writer called "a great compromise between size and capacity." The 2.2-inch height also let the tips tuck in just ahead of the bumper. For more on sizing, see our Oval Exhaust Tubing FAQ.

Routing an Oval System

The story explains that a round bend can be rotated to change direction in two planes at once, while an oval bend turns only side to side or up and down. That takes more planning when ordering parts, but the writer found it made a symmetrical, level system easier to achieve.

The Parts Used

• Classic Performance Products cast manifolds and Hooker Blackheart intermediate pipes
• A Summit Racing 2.5 to 3-inch transition, then a Granatelli Motor Sports round-to-oval adapter (PN 313531)
• Granatelli Motor Sports 5-foot straight oval tubing (PN 313535), 90-degree vertical bends (PN 313539) and 45-degree horizontal bends (PN 313536)
• Granatelli Motor Sports stainless mufflers (PN 313541), placed behind the cab to cut drone
• An H-pipe behind the transmission and slip-on flanges so the system comes apart in sections

Fabrication Tips From the Build

The article covers cleaning parts with acetone before TIG welding, purging the tubing with argon to get full penetration and avoid sugaring, sealing flanges with high-temp RTV and supporting the system with stainless hangers near the mufflers and at the tail.

Read the full article at Classic Truck Performance