Some parts of the country are better suited for drag racing than others. Anything with high altitude is going to have a negative impact on elapsed times. However, Utah’s Jim Barth is beating the odds with his ’91 Corvette. Barth lives in Utah, and races at 7,000 feet. Sometimes the DA is over 8,500 feet, but his Corvette still runs 10.0s at over 140 mph.

Barth gets it done thanks to a 464ci tall deck small block Chevy (Dart Iron Eagle block) with 12.25:1 compression, a Crane solid roller cam, ported TPIS Mini-Ram intake, TPIS 1,350-cfm Monoblade throttle body, a McLeod dual-disc clutch, a stock ZF 6-speed transmission, a Ford 9-in rear with a 4-link set-up, and Strange Engineering rear end components. To make up for the lack of air, Barth brings his own atmosphere thanks to a NOS plate nitrous plate system. Perhaps the biggest piece of this puzzle is the cylinder heads Barth chose for the combination. Barth builds engines on the side, mostly for guys on CorvetteForums.com within the C4 platform, and he knows what works.

Barth chose Air Flow Research (AFR) off-the-shelf 245cc heads for the combo. Technically, the head is AFR’s 245cc SBC Eliminator 23-degree NPP racing head. The NPP stands for No Pushrod Pinch. This design makes it possible for either conventional pushrod alignment or for offset lifters where the pushrod isn’t straight up and down. The 245cc is best suited for what AFR says are, “max effort applications.” AFR says the 245cc is its best-flowing 23-degree head it sells, and the No Pushrod Pinch feature also allows for an intake port with a more direct shot at the back of the valve. The head also features a more consistent cross sectional area and velocity profile. “They work really well on a large cubic inch engine,” Barth says. “Plus, they don’t require super-exotic components on other parts of the combination.”

Velocity and port design is the key to horsepower, but the 245cc head also benefits from a ¼-in raised exhaust port when compared to a factory L98 head. The 245cc head necessitates a shaft-mount rocker system, and Barth uses a Crower shaft-mount rocker set-up on his, but AFR says the 245cc is still a conventional bolt-on, non-raised runner intake port configuration.

Safe to say, they’re doing well as part of Jim Barth’s combination.