the smaller tube is just used to replace that whole cluster of metal tubing that is still dangling. it is right under the longer tube that you should have used to connect the intake to the valve cover. if you tug on the metal tubing cluster, you will notice that there is only one thing still connected to it.. it goes from tube to metal to tube. just rip that whole cluster out and connect the 2 end with that smaller hose, be carefull because antifreeze will start to leak out.. might as well do a flush while your at it..