Grudge match HELP!

I agree with the drag radials. I know you can't fit much tire under that car, but keep them small, in diameter, to help with the gear ratio. A d-loop would be a good idea, too.
Also, what rpm do you shift at? Too low, and the engine will drop below it's power range after the shift. Years ago, I had a stock '72 340 Demon that wouldn't rev above 5200. I shimmed the valve springs at the advice of a friend, then shifted at 6000 (auto), going through the traps at 6500 in 2nd gear (it had 3.23's). It's been too long to remember the exact results, but it was the biggest gain I got tuning the stock engine. FYI-Your trap rpm's will be lower on a "bad air" day.
The other big gain I saw was from loosening the secondary air flap on the Thermoquad. You mentioned a light spring. I guess you've done that. You have a light car and a decent rear gear, it'll like that, depending on the torque convertor's stall.
You should pick up a couple tenth's just with the better air that he ran with.
Is he doing anything to pick his car up?