The BLACKHAWK was the last aircraft produced by Curtiss-Wright. She was a big girl @ 62 ft long and a 60 ft span weighing 49,900lb @ MTOGW. I can't imagine what might have happened if the 4 20MM cannons located in the rotating, fully traversing nose cone had ever been fired with the cannons deflected 90 degrees in flight. but it would have been one for the ages!! 'want to fire again?' "yeah, but let us shove our eyeballs back in their sockets first"
I don't think you could convert anything into the XP-87 from a kit, I think there was a vac kit of it years ago