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Not saying you couldn't get it Bill, it was available but Copo 9511 necessary for '69 cars.
A few existing '69 4:56 also 4:88 cars w/ original paperwork are known and sure enough, the 9511 is indeed noted.
We went through it here a few times over the years also more info has come to light on other sites since too so best Google around and you'll see it's true.
~ Pete
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