your amp is 1 ohm stable then it will run perfectly fine at 1.33 ohm's. to be honest it would honestly be louder to run those 3 subs as opposed to like 2 dvc 4 ohm subs running down to a 1 ohm load. you will have a very minimal amount of peak or rms wattage difference between 1.33 and 1. your amp will run it fine my friend.
keep it thumpin,
adam