You said in your first post that it was a 69 SS427 Impala convertible but I see it has drum brakes. Do you have any documentation on the car? Not calling it fake, the reason I am asking is I purchased a 335 hp 427 out of a '69 SS427 Custom Coupe in the early 80's. Not only was it a 335 hp, but it too had drum brakes though both were said to have not been available with the Z24 option. Somewhere I have the POP for the car that I got the engine out of and it would just be nice to know that maybe the literature is wrong and drum brakes could be had as well as the 335 hp. My '69 SS427 convert has the 390 hp and discs so just asking.
