there's a big difference between factory 343hp carbs and those edelbrocks. i have race specs for the factory 2970s and 2971s carbs but they're a smaller different carb than the edelbrocks. long shot might be finding old 400cfm or 500cfm carter performance carbs from back in the '70's. when edelbrock made their "smaller" carb all they did was screw up the primary booster. crummy carbs in my opinion.