Well, I've had no wedge megas, but a few hemi mega. I have one now that just dynoed at 1260, and I'm going to spray it with at least 400 on the hit. I've sprayed them with 500 numerous times at slightly less na power so I've had zero issues doing so, unfilled, and at 4.53 or bigger bore. The ones I've done in iron have no center counterweights either, and they all see 8200 + in the traps.

Breaking a good mega block at 1000hp sounds like a serious mistake on some part of the build, and or tune.