Determining the right mosfet current for a h bridge

Hie again. i am about to place an order for some n channel mosfets for my h bridge and there is a few things id like to verify.
i will be making a 4wd robot with skid steer configuration using 4 motors, so there will be 2 h bridges, one controlling 2 motors. 
Since my motors stall  at 42A each, will a 120A for each h bridge be enough? or is 80A enough since these motors are quite impossible to stall?

here is my chosen Fet
http://au.element14.com/jsp/search/productdetail.jsp?sku=2253787