You asked and vapor told you to sleeve it. He is right. It might not crack but why not do it right? It would suck to spend the money on building the motor then to crack a sleeve. I made that mistake myself. You might think you want to only push a certain amount of power untill you get it built and then when you try for that extra 10 whp your sleeve cracks. Like john said if you want to save a little and have a strong block without sleeving it then go with an LS. I know marlin sprays his B20 and has over 200whp. That doesnt mean one of his sleeves wont crack. If i had sleeved my motor i would have another 150+whp without changing anything. Some people are lucky to see 150whp by itself. If you are going FI there is no question what you should do.