in 1.1.x can i set up a group that will keep each members for 7 days before allowing them to post ?
There are no time limit facilities in SMF Membergroups so no, you can't. There may be a modification that gives this feature but I can only find this one (http://custom.simplemachines.org/mods/index.php?mod=1915) which might help you.
That's a nice mod, but not quite what I'm looking for ..
Perhaps this should be moved to mod requests then?