What to do to get a quicker launch...

Are you using a pinion snubber?

SS springs?

I would deninitely recommend an 8-3/4 sure grip larger gears, pinion snubber, and ss springs.
I am running all of these on my car with 3.23 gears and it hooks like mad, but I am also mini tubbed and have 12" tread width and mickey thompson sportsman pro tires.
I also have a four speed manual trans.

Also run a torque strap to keep the motor from lurching under torque, maybe even solid motor mounts too, but a torque strap is really all you need.

Don't forget a driveshaft loop.