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The 68-69 'Drop tops' with factory A/C that actually work are bringing very big $$.
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You might want to define "very big $$"

If you had a nicely restored or excellent original 69 SS427 convert with working factory air, you'd be hard pressed to get $30K out of it. In today's market that can hardly raise an eyebrow. As Rick says, for whatever reason, these cars just do not command big bucks.
The 67 and 68 SS427 had unique hoods; the 69 SS427 uses the same hood as any other 69 Impala