The car is a duster weighing 3200lbs w/driver. Has a .030 440 with 10:1 flat tops, 440 source heads, Mopar .590 solid cam, Holley 750 DP, 727, Turbo Action Valve body, 8" 5000 stall convertor, Dana 60 with 456, shifting at 6000. I freshened the engine up this winter and installed new valve springs and had the heads ported this winter (went from 255 CFM to 287 CFM at 600 lift). Car picked up almost a whole tenth in the 1/8. I think the 750 could be limiting the overall performance, but not sure. The car has been best of 6.79 @ 100 with 1.48 60 fts.
My combo is not that much different than yours.
Differences.....
3325#
.040" over 440 with 12:1
Similar flowing iron heads
Ultradyne cam similar in specs to the Mopar .590"
Shift @ 6,500 and trap @ 7,000
6.43 & 105+ 1/8th mile with a 1050 Dominator that was a plug killer
Sent my carb to Thumperdart and it is now snappy & happy
I figure a couple tenths quicker than the stock Holley set-up.
Find a used 1050 Dommy in good shape, send it to Thumperdart for re-work or get a new custom carb from him. You will be shocked at the results!