Unported head quickness?

360, J heads, XE268H, LD340, Holley 750DP, Dougs headers, MSD ignition, 904, 2500 hughes converter, 7 1/4" 2.73 gears, 245/60/14 BFG TA radials. Dyno'd at 345hp/395-400tq.

Wt 3250

Ran 14.20 at 103.7-104 in Las Vegas with no tuning change to the carb, stock jetting. Car was babied off the line, 2.20 60's. If the car could leave well it's capable of high 12's even at that elevation.