I think thats a relief valve for the cooling system. if you look in the videao there is a tank on the front of the truck just behind the weight. that truck is not a street truck, they trailer it to the pulls. a lot of the tractor pullers use those tanks and they only put like a gallon or so of water in them after the cooling system is full. the rest it all ice. I used to drive for my uncle in tractor puling and thats the setup we had in our rig. the temps were so extreme that we started with ice and ended up with boiling water ant the end of the track. I stand corrected about the motor in that truck, it is an INTERNATIONAL DT 466 motor, not a cat.
as far as getting beat, i dont think I did too bad considering I drove my truck there. they did all those mods to it and only won by a few inches against a DAILY DRIVER! lol