can i ask what so special about the x block and what year did they come in or is this a aftermarket block, and I'm cures about what kind of heads you plan on using only reason, I'm asking is next year I'm putting a 70 challenger together 4 speed car i have a 6 pack set up for it already and i think a stroker 440 small block would be a great set up i like, what yours is looking like sorry to pry. I'm looking to spend 9to 12 grand on the engine . will be the budget.