I had a 3800# non-Mopar running 1.30 60'times running the rear tires in the 9psi range. My Guess is you're real close to your ideal times. I'd start playing with the rear shocks now, and would even consider turning down (yeah, it's a TON of work & hard on your lathe) the t-bars. Don't laugh---I was talking to a well-known formwer P/S racer from back in the day & he did just that! Caught s@#t from the Mopar engineers who said it wouldn't work but it cured his problem & that car's still around.