Kurt;
With your vehicle weight and limited gearing, you're going to want to concentrate on low-end and mid-range torque, not higher rpm HP. You're looking at a usable power range of ~3000-6000 rpm. Anything much over that is going to be wasted here.
In that regards, you might want to consider shelving the rectangle port heads and going to a set of open chamber oval ports, such as the 049's or 781's. (A set of 820's might work as well, but you'll have to watch the dome-chamber fit). You're also going to have to keep the cam timing fairly conservative as well to keep the power range down where it's going to do you the most good. Again, a flat tappet will suffice at this level. (FWIW, look at how quick guys are running with the factory L78/LS6 143 cams, and they're only .520" lift and 242° @ .050)
A wide ratio trans will be a benefit as well here due to the additional torque multiplication. You're going to have to concentrate hard on covering the first 60' and 330' as quickly as possible as that's where your e.t. is going to come from.
Again, the weight and limited gearing are going to make things a bit more difficult, but if you concentrate on keeping the power range down where you can use it and spend a little time to refine the combination, you'll get there. Keep one key factor in mind throughout this--the car itself has to work...there is a
lot of e.t. to be found with the hood
closed.
And you're welcome, I'm glad to help however/whenever I can.
Eric