After upgrade to 1.6.4 do i need delete install folder in ftp
No, you don't. Feel free if you want to, but there's no need.
ok guys i delete it one rep+ for support
one more question about upgrade when everything goes nice with upgrade do i must do anything more with template or whatever??
Go to ACP > Templates & Style > Templates > Find Updated Templates > this is a list of templates that you've edited that have since been edited by the upgrade script, you'll need to revert these back to default to make sure the code is up to date. You can view a diff report on them first to make sure you don't lose any changes you want to keep.
only see this to reverte into default header_welcomeblock_member_admin
^ fine, revert only it to the original ...