You need to pull the ABS unit out of the car or you will not have the proper brake proportioning. The ABS controls this.
I eliminated my ABS with an SJM Manufacturing ABS Delete Kit.
http://www.sjmmanufacturing.com/cam_brk_ls1.html
The kit comes with a Wilwood Proportioning valve and pre-bent lines. You will need to cut the lines and connect them into a T fitting.
Call them up and ask to speak to Steve. He know his stuff! He will also tell you the easy way to shut off the ABS INOP, BRAKE, and TCS lights without breaking bulbs or rigging.
After you have the kit installed, you will need to take the car out and adjust the valve so that the rear wheels no longer lock up before the fronts.