I had my 440 Challenger weighed at the strip last summer. Over the years I have removed a lot of weight from the car. In particular weight from the front half. Manual brakes/steering, no heater or air con, ally radiator, ally intake, plastic front bumper, battery moved to the rear etc etc.
But stock iron heads and full stock interior.
Total weight of car with full tank of fuel was 3705lbs.
Total race weight with me in the car was 3890lbs.
Front - Rear weight was split 54.9% - 45.1% (pretty good for an iron head big block car I think).
Side to side weight distribution was 50.8% Left and 49.2% Right.
That's pretty consistent with what I've seen over the years. However, for some reason a lot of people don't believe that E bodies weigh almost as much as B bodies because they are shorter. Here is some proof.
The distribution is pretty fair, as you said. You have moved a few % points around for the effort, and while seemingly small, it does help. To get much more aggressive with weight reduction or distribution requires liberal use of fiberglass and aluminum.
My '74 Challenger small block was a bit over 3650 with me and 1/2 tank of gas in stock form. I''ve since done some reduction/redistribution on it, but haven't weighed it to see what progress I've made. Earlier models might be a bit lighter.
Do you have any idea what there race weight was for the cars in the TA series?
Race weights for the trans am series were initally 2900#. By 1970, that had been raised to 3200# with a 3400# max including fuel and driver. Any special production cars had to have 2500 units built to homologate the car, up from 500 initially specified. By '70, dual carbs were gone and any 4 speed or brake combination could be used so long as they were listed in the manufacturers parts books and available over the counter.