My stock stroke 340 engine has a crack in 1 cylinder. I want to sleeve that cylinder and rebuild as a .040 over 500+ HP stroker but looking for advice first to see if It would be ok or if I would need an unsleeved block? I would feel safer going 60 over with an uncracked block than running a sleeved 500+hp block with the 2"+ crack in my block (see pic). The guys at Dandy Engines here are famous for their aluminum 1000+HP gm and fords but have no experience with iron mopar 340's here in Australia so I'm falling back on the experience of the guys back home who've been there, done that and hoping for some solid advice. It'll cost me a LOT to ship a used 340 over so just wondering how much a cracked block will take trying to squeeze the piss out of it with stroked crank, 11:1, expensive ported eddy heads, .600ish list cam etc. Im I asking for trouble or...? They mentioned a greater tendency for core shift having a cracked block with this build.