73 Duster build named Fred
5800 is in the ball park for your peak torque.
my black R/T was horrible in the 60'. i had cal tracs and it didn't matter what i did, there was no change in 60'.
i talked to John Calvert several times over the phone about it. i switched to his 90/10 rear shocks and still no difference. next phone call he said i needed his front shocks. bought them, disappointed as no better in the 60'.
after 2 years and trying ever setting possible, i ended up wishing i never bought cal tracs.
i think the only way you will get your 60' to improve is a transbrake. i made the jump to TB and never will FB again. 1.39 to 1.29 is a feeling you don't forget