from a roll depends also.......if your in gear and not downshifting, lighter is better.
If your down shifting and have the extra .1 second to let the rpms climb before before dumping the clutch, you'll slingshot ahead.....
My D15B7 12 lb. vs. 18 lb. was .15 seconds difference in the 1/4 mile, all of it was in the first 60 feet. 18 lb. was faster.
But look at the times I posted from 8/2005, I was about the same with more HP, smaller slicks, and the 12 lb. light flywheel. You have to get the sled moving first, that is the biggest balance of power and traction.
Now once the car is moving, the lighter should be faster, but that depends on the driver.
Now road racing, WHOLE different ball game, lighter is better, esp. so you don't shock the driveline on downshifts under threshold braking.