I am running 3.23'as with my 461 and M20 4-speed right now. The acceleration is awesome and I don't rev above 3K doing 65 MPH. I would like to maybe put in some 3.08's but that is as high as I would go. A pontiac engine is known for it's low end torque and doesn't need the 3.73's or lower gears a Small block Chevy does for performance. There is a guy here on FGF that is running 2.56's with his 400 and he smokes the tires ALL of the time leaving a parking lot or just driving down the road.