You'll gain even more from relocating the battery if its as far back as you can get. So not the high up near the rear seat back but even further back by the bumper. If a 20lb battery is placed say 2ft behind the rear axle, it will create a moment about the axle and is like removing an additional 5lb right off the Front axle of a 3600lb B-body.


Removing rear weight hurts weight distribution but can still have its benefits. Hyperco rear fiberglass Leafs will shave a good 70lbs of static weight off the car but most of it is UnSprung weight, which is a great thing for a portly live axle.