Unported head quickness?

1975 Duster 3250 race ready with driver
440 .030 over 10.5:1 (Stock rods with ARP rod bolts with Speed Pro Pistons)
OOTB 440 source stealth heads with upgraded 10 degree locks
Weiand Intake with 2" open spacer
Holly 750 DP
MP .590 solid camshaft
727 with 5000 stall convertor
Dana 60 with 4.56
29.5x13.5 rear tire
Shifted at 6000, went thru traps 6400-6600.

Ran low 11.teens in good air. More typical 11.20's on a normal day