Hi burnzee20 Total 1963 Impala SS 2DR HT produced was 399,224 . Never heard of, nor saw anywhere, about 1963 Impala SS that had a 3 speed Std , which would have had to be 3 on the tree., which the plain Impala had. All 1963 Impala SS had the bucket seats, with console . Most of them being powerglide or 4 speed std on the floor. I would say that someone along the way, dressed an Impala into a Super Sport. . Does it have the engine turned moldings on the sides , and also in the dash area, plus SS badging. Is the 3peed on the steering column or on the floor. If it is three speed on the floor , someone substituted here. One thing, I can tell you, from 1961 - 1965 a total of 43,755 409 engines were produced. This does not include trucks. I 've had two 1963s over the years. One being Impala 2DR HT / 283 poweglide, and my last was an Impala SS 2 DR HT , 409 /340 HP powerglide car, which you see in the picture.. Hope this is of help.