Maximum rpm for SB

I've been wondering about this myself, because mine was rebuilt a few years ago before I got it and I don't know what's in it, parts-wise. It seems healthy and pulls strong up to about 5500, which is all the higher I've pushed it so far. Don't want to abuse it, 'cause it is mainly street-driven and I want it to last until I'm ready to put a big block in there.