Door Slammer plans

Sup guys I've been milling over a combo that in my head will be awesome so give me some input on what you think. The car is a 79 impala stripped to a race weight of about 3400 lbs. On my dyno simulator I've got a 383 stroker with pontiac motorsport heads that makes about 600 horspower and about 620 ft-lbs of torque. I plan on using a th400 with the stock rearend but in seriously upgraded form, or should I just use a 9" ford? I understand its stronger but I also understand that they loose up to 12% power due to mechanical ineffiency. I've read that a 7.5 if built right can withstand about 700 ponies has anyone done this? anyway if I can get this thing to hook does anyone have a guess as to what it will run through the lights? The gear ratio will prolly be a 3.73 but with this much torque maybe a 3.55? Just need some constructive critizism thanks in advance fellas.