Changing the rear gear will give you a big increase off the line. I'd wait until I tried them before starting to think about a tranny swap. Those powerglides are very popular with drag racers. If you do a lot of highway driving then an overdrive is the way to go. I'd say changing the intake manifold will make more difference. That torker manifold operates from 3500 rpm to 7000 rpm. It's called a toker but that's just the name. You will get better off line power and mileage with a stock manifold, a performer or a performer rpm. I think the performer would be best suited to your car, it operates from idle to 5500 rpm and is a stock bolt on. My opinion anyway.
