Mopar R3 Block
Its a custom CP piston that was in the engine when I bought it so don't have the specs your after, was built originally for an 8.50 index racer brand new but the guy relocated out of country so he bailed on it and the engine is also setup for nitrous and if memory serves me correct it was 13.5-1 and then Brett went through the engine a couple years later to update some things and he cut the heads a touch so now it's roughly 14-1