Installing an adjustable clutch would be highly recommended.

605" Hemi is going to hold quite a bit of inertia in it's rotating assy, 727 ratios say it it would dump about 65% of that inertia on 7500rpm 1st to 2nd shift. All that energy has to go somewhere, either the clutch, tires, or the transmission has to slip to keep the drivetrain alive. Dual disc clutch says the clutch isn't going to be doing much slipping, so you are left with either the tires or the transmission slipping on the 1/2 shift. 65% of that inertia represents quite a bit of energy to waste in a wheelspeed spike, but the alternative is slipping the transmission's clutches long enough to recover some of that energy. Adding an adjustable clutch would allow you to recover more of that inertia without smoking the transmission's clutches.

Grant