Well we have made 680 on a non sleeved block here in GA, and 630 on a h22 stock sleeves and 480 on a gsr non sleeved. If i where to build another motor i wouldnt get it sleeved again.
You just need to sit down and figure out what you want,HP wise.
Anything under 650 i wouldnt get a block sleeved, also you can make over 600hp with a 60-1.I have a dyno sheet to prove that,
I personally think u can build a 600hp car for way under 8k. I have done it and have seen many people do it as well!!

The 1st question you need to ask youeself is what you really want?