This is why LS-Vtec motors get a bad rep.
Do it the right way & build the shit out of your block. Then you won't ahve to worry bout anything breaking.
Bore it / Sleeve it / Forged Internals = no breakage! & High reving power house!
If you leave the block stock.. you have a ticking time bomb in your engine bay.. it's just a matter of time b4 it blows witht that vtec head on there
just my .02