There is no need to remove the original brackets. But if you want to, it's held on by several spot welds. These are recognizable by slight circular indentations in the surface of the metal. Or you could just cut off the part that's sticking out. Just don't cut into the shock tower.
Proud owner of a '65 289 coupe w/ C4. Equipped with Edelbrock Performer intake K&N air filter, and 600 cfm carb, Comp Cams Xtreme Energy valvetrain, Comp Cams XE262H cam, MSD ignition, and ported heads. Suspended by 600# 1" drop front and stock rear springs, KYB shocks, 1" front sway bar, 1" Shelby drop, Griggs Racing GR350 rear suspension