Unported head quickness?

'71 cuda 340 all steel....3550lbs?....back in 1987 at Santa Pod

stock '71 motor, 2.02/1.60 no porting
DC .590" solid flat tappet
Strip Dominator+2" spacer
850DP
1.3/4" Hedman Chassis Headers
MSD6A
Manual 727, 4200 stall
Stock Leaf springs+Snubber
4.30 gears
Good Year 10x28"
12.39@108.5

Hit it with a 250 shot went 11.01@123