Well my only B1 experience is with low deck "baby" motors. My first was a 451" in the stone age in a tube chassis Daytona. It went 9.0's at 149 all out using a out of the box heads, stock block and crank at 2650lbs. My next one was a 511 low deck that I had in my 67 Valiant 10.5 car. I never ran it on the bottle but it went 9.0's at 3470lbs with a set of fully ported B1's, stock filled block, aluminum caps, and an Ohio 4.25" crank. Neither of those were dynoed but made pretty good power and were pretty basic parts. The motor that is now in the Cuda is 4.50" bore 4.125 stroke low deck in at 525". It has been dynoed and makes right at 1050hp with a set of B1MC's, Callies crank, and KB block.

In the end I think you can make 850hp pretty easily. Wont take any exotic parts to get there or huge compression ratio's. My 451 was about 13 to 1, the Valiant was 13.5 to 1 and my current engine is 15 to 1. I think the stock block stuff will live fine if you keep the bobweight light and do not have any detonation issues. The caps and girdle will help and IMO the block fill will as well.