06D would have your car leaving Flint Michigan's back door during the fourth week of June back in 1966.
I can remember before demand drove the prices up; when you could buy all of the SS badges from your Chevy Service center for about $25 bucks. They often had all of the parts in a pile unboxed in the front display case by the cash register to tempt you when you walked in to buy a new exhaust donut to quiet an exhaust leak, or whatever other Chevy part that you needed that wasn't sitting on K-mart's shelf (pre Wal-Mart, and pre credit card days when people made and carried cash on them).
No big deal as I said it is only a trim package. If you have most of it look for a set of buckets and complete the transition. As to the performance aspect you can buy new springs, shocks brakes and of course upgrade the power train to make it into a killer muscle car.
Your car was made back in the days when Chevy offered only three hot rods; the 427 Impala SS (often it was installed in a stripped down Biscayne instead of the heavier Impala, and was a different RPO option with different badging and hood than the SS trim package), the Chevelle SS 396, and the Chevy II with an L-79 RPO code 350 horse 327 four speed.