brake lockout?

[kev63rod]

hi just bought a 64 chevy 4x4 and found this underneath. was wondering if this is a lockout to lock the front brakes up for burnouts or what?

here is a pic of the truck. not the best as it was dark outside. 70's axle up front with dics brakes. under the hood it has power steering, power brakes. looks to be a 70'ish 350 motor with hei ingnition. newer auto trans/trans case. inside it has a 70's column and brand new carpet. also came with a new windshield and all the weather stripping for the cab along with a boxfull of crome parts for the grill and tailights. also has a new intake and gaskets along with a used holly 4 barrel laying on the floor. havent heard it run but finnally got it to crank after going through the wire harness. (wire nuts, butt splices, melted wires, and all that fun stuff) i think im not getting spark but havent had a chance to check. it didnt sound to good when it was cranking over though. had some kinda noise in the frontend of the motor. maybe timing chain. the kid i bought it from said he had it running, but i have my doubts.