For a Kirkham 427 car, go with the FE.
How about a street driven, occasional track day, turnkey FE engine in the neighborhood of 600hp?
If you're going to pay for a new 427 block, don't stop at 427 cubic inches. The more cubic inches you have, the more horsepower you can make without making the engine un-streetable. 482ci is a very common size for these.