A filibuster to block a vote on a bill is possible?

Only in the senate which is almost unrestrained

Yes it is possible. Under the new rules, if senators wish to block a bill or nominee after the motion to proceed, they will need to be present in the Senate and debate. Following the changes, 60 votes are still required to overcome a filibuster to pass legislation and confirm nominees and the "silent filibuster"-where senators can filibuster even if they leave the floor-remained in place