Boss 429. The Super Cobra Jet was rated for 375 bhp while the 429 Cobra Jet was rated at 370 bhp. 1970 was the final year for the Shelby Cobra's. A total of 40,970 Mach 1's were produced, 7,643 convertibles, 13,581 Grande Hardtop Coupes, 6,318 Boss 302's and 498 Boss 429s...