The reality of most "dyno queen" engines is that they make thier big figure for 5 seconds on the dyno, and then get stuck in a car and turned down.

NO ONE will be running a 1000bhp YB and using it hard reguarly with that much power all being used, I'll say that much, the block would just fatigue and fall apart IMHO if they did, these shitty old lumps of cast pig iron just arent up to it.