1972 455HO Q-jets are of the normal 750cfm casting. The 1971 455HO Q-jets (7041267, 7041268, 7041270, 7041273) were the only carbs to have the primary booster ring not cast in. The booster ring delete help curb nozzle drip and increased air flow to 800cfm. That is what makes them so desirable for performance.
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