Ls6 454 block?

I have my fathers camaro that has been sitting around for roughly 30 years. He tells me that the engine is a 454 Ls6, I just want to verify that is what I am dealing with before I start ordering parts to rebuild it. The code is 3963512, it has 4 bolt main. date code is C31 70 I'm guessing that means march 31st 1970, not sure though. Any info is greatly appreciated.

the 512 block is $$$$$$$$$$ get the crank number that will tell you more as well if it is all numbers match engine you have a very pricy engine