The 400 sb is from a suburban, sounds stock. My interest was the torque the engine should have. I like the OD trans for the steeper gearing to help launch the car and then if cruising the interstate gaining the advantage of the od. I just don't remember any Chevy 300 hp 327s ever feeling strong at take off withthe PG. With the od trans and this engine, why not just stay in 3rd until road road speed fast enough to let the engine lay at sub 2000rpm in od ? The rear end is not a posi-trac and I am only guessing the ratio is 3.08:1 . I will have to check to see what actual ratio is. I believe the 6cyl/pg was common with this gear. Thanx for all the comments/advise all have offered.