Best place for ballast in an E body is the rear floor. Made my old car work better when I removed weights from the trunk to the center, above the axle, in the passenger compartment. I suppose if a car had the rear seat, ballast would work good, under the seat or behind the front seats. Weight done this way adds to the CG. Weight added to the trunk is farther from CG and makes it harder for the car to rotate.
Please make sure to secure the ballast, if it is inside the car!
