When we did my 440 kit, we did nothing to the cases. I have never heard of anyone having to work on the cases when puting in a 440 or lower kit. Maybe with the larger kits. Sorry to hear about your problem. I would bet that it was not bored correct and there was play or out of round for some reason for it to crack. the only proble that I had with mine after running it for 2+ years was blowing head gaskets. The fix for this is to put in the larger studs. This fixed the problem.

 

Well this isn't the first sleeve to crack, FST Mickey Dunlap explained the case interference problem on some engines. He also has an 89mm bore which makes the sleeve pretty thin at the bottom.

 

not all aftermarket sleeves are the same. i run a LA sleeve and i believe it is good for a 426-445. this is a tapered sleeve. so, it get thinner down near the bottom. some companies, i believe sparks, uses a non-tapered sleeve and the cases must be bored. most reputable engine builders will say to at least clean the rough edges up on the case when putting in a aftermarket sleeve that will fit the pistons that mine fits. there is no way i would put in a 440 and not check the sleeve clearance at least. i did bore mine out a bit. i didn't need to go much as my sleeve did fit down in teh case but there were a few edges that i wanted to clean up. check this out. it will explain everything:

http://www.exriders.com/vbb/showthre...threadid=83162