couple of questions for ya;
first off, how is the car primarily used? street/strip, mostly strip etc.
what shocks are you running in the rear, and are they adjustable?
front springs? ft shocks? tire pressure?
I looked up the SSM bars, and not to offend, but they look like glorified slapper bars.
IMHO, a car with as much power as you're making needs to spply the tire pretty hard and keep it applied on a radial, especially with a stick. An adjustable setup will help immensely.
I also agree that i've never seen a radial tire work in a high power stick application, so you've got some testing to do
My 68 only makes 470 to the tires from a 302, and goes 1.58 60ft. with a stick. I'm a BIG fan of the Caltrac bars and adjustable rear shocks...they dropped my 60ft from 1.93s to 1.58.
Take some vids and post them up, maybe we can put our collective noodles together and get you sorted out.
Hope that helps, and good luck!
Duke