The block, with a girdle, will be fine. It's the pistons I'd be worried about. The picture below shows a piston after I magnafluxed it. All 8 were like this, and he was running 8 (real) pounds of boost. I see it alot on boosted 5.0's. It's usually caused by bolting a blower on a stock bottom end, which is fine as long as you don't start cranking up the boost. Anyway, make sure you get yourself a good set of well fitted pistons.
Take care,
-Chris
