I am not saying that Royce does not know his poop, cause he does, but..........
I was told this by a machinist some years ago. He said that much over 500 HP and the cylinder walls just usually dont last long. I would imagine that this has to do with the amount of overbore, the original thickness of the cylinders, and the block material makup which is largely dictated by when it was made. Typically the early model blocks tend to have more nickel content from what I understand, which makes them somewhat stronger.
As with any failure, the block will last a while. If is is something that only gets beat on once in a while, it may last a long time. If it is a drag car that sees 5-10 full throttle runs a week, then failure will be much faster. This all has to do with material fatigue qualities. Kindof like running stock rods in an 8000RPM engine. They will last once or twice or twenty times......but they will let go eventually. To me, blocks are the same way if you start pushing the limits.
After hearing this news about the blocks I started paying attention when I saw block failures on the web and such. Most of the time it seems to be cracked cylinders, but that has just been my observation. So many people get caught up in the main bolt style and count, but I personally have seen alot more cracked cylinders than cracked main webs.
That information is what prompted me to tall fill my block on my turbo engine. Everyone screams about the mains on a 400 being weak, but if you do some research you will find that RPM is the key component in making things go boom more than the power output. In NA engines the two are sortof the same, but forced induction engines can make alot of power in low RPM range. What this added power does is add alot more cylinder pressure and stress. Under those stresses the cylinders begin to "walk" around a little bit. Eventually this will cause a crack, but the grout can prevent this. But the good news is that by keeping RPM down, you will likely have worry about the mains or the crank letting go.
Kindof comes down to this.....When you double or triple the intended power output of an engine, something WILL break. It is just a matter of keeping it together as long as you can.
If I were you, I would at the very least have a short fill done to limit the movement of the cylinders. With a short fill you can still run on the street without cooling issues. This will also help stabilize the main web area. The whole deal with things cracking is because of movement. Making it as rigid as possible will help.
I dont run a machine shop and I have never had either one of these failures. I am just offering what I have been told and have observed since coming upon the information
Chris
