I like the 400 too, built with attention and not just a slapped together backyard job...great torque for a plow truck. I've always felt the 400 got a bad rap, part from people trying to wind it like a 327 and part from getting worked on like any other sbc...biggest sin was swapping heads with no clue what steam holes are or how to add them to non-400 heads. My preference is the 509 casting block because it is the higher nickel content, and a 2 bolt block because there is more meat there to drill it to a 4 bolt splayed. I prefer to keep them around .030, will run a .040 but nervous above that. Also prefer decking the block and studs for the heads, and internal balanced crank. For any 400, as long as I've kept a good cooling system, they never let me down.