I purchased my 70 ss 15 years ago and the previous owner had claimed it was 390 hp. I do not have the build sheet because the car was re upholstered ,I do have the protecto plate with the crn code. Over the years I have seen 2 other cars in classified ads claiming the same thing .I did some research and found that there was a 390 hp 454 offered in the corvette and impala is it possible some of these made it into the mcss and how could you tell it apart from the 360 hp even though they share the same crn code.