It is in fact a real authentic Super Sport car, and DID come with a Big Block engine. The core support for the big block cars came from the factory with a 2 foot gap to house the larger 4 core radiator, which mine has. Compared to the small blocks which came with a 1' 6" gap to fit a smaller radiator. It originally came with a 375hp, 396. It currently has a big block 427 from a '66 corvette. I haven't had the engine apart very much so I really can't tell 100%. But the serial #'s imply that it's the 427 Vette engine so eventually I'll have to find a #'s matching engine. Before I bought the car it had sat in a garage for 8 years. And before that it was raced every so often. It only has 74k original miles on it. The lack of driving actually saved the car, since it has NO RUST. And since it was from Missouri, being a southern state with better climate than where I live now in Chicago. Although it is currently not numbers matching, im working to bring it back to the day it rolled off the assembly line, I've already found a replacement back seat for when I remove the roll cage years from now. Along with a heater box. so slowly its going to return to its original state, the way it should be. I can't stand when people take these old cars and "chip foose" the hell out of them with new everything and a set of ghetto rims on an old body and say its a muscle car, when its really just a bad joke.