360 to a 408 how much quicker

old combo was a 360 30 over 10.7:1, edelbrock heads ,Xtreme Energy Retro-Fit Hydraulic Roller-dur@ 0.050 242 248 valve lift .549 .544 ,crane roller rockers, air gap intake , 750 dp speed demon. it in a 69 dart 4 speed with 4.11 gears . it now has a 408 scat rotating assembly 10:1 with all the parts from the old engine. it ran a 12.20 with the 360cu engine,how much do you guys think it will pick up?