That's the difference between standard port heads like I assume you have and Max Wedge. With my heads and cam, it just flat out needs more gear and converter to ET like the MPH says it should.
My old 451 had a better 60' than this combo as well, but it had Eddy RPMs, a 4500 converter and 4.10s. That combo went 6.71 @ 101 with a 1.44 60'. I know my current converter and gear are far from optimum. I just need to decide if I want to give up the driveability of 3.55 gears for a little ET. I really want to spray it down the road so it's probably best left alone. Trust me, this car dead hooks but look at the chassis dyno differences at a few RPMS...