[Mike Mans]

You've got a combination that definitely doesn't need anything too fancy. If you found the budget, I would go with an off-the-shelf AFCO double adjustable. But I understand if that's not the case.

I'm guessing you've got a pretty traditional 2.74 low gear and a 4.88 rear gear, which in that car and probably 51%+ weight on the back - should be able to stand up and leave nicely. A few things I would suggest you peek at would be ride heights and front springs. With you in the car, if you measure from the ground to the rear fender lip and you're down around 28" it's going to try and put the car into a compression action leaving the starting line. If you run the back a little higher at ride height (29.5"+), the natural tendency may be to go more into extension at the hit. These different setups of course are asking the shocks to do different things, so it's pretty impactful.

Also, check your pinion angle. I would suggest 1-1/5* down will be a good baseline for an automatic car. If you don't have an adjustable torque arm, you'll probably have to play with ride height to help this a little bit.

As for front springs (which are very affordable), I would suggest around a 275lb/in spring up there. You want something with enough stored energy to help really push the front end up at the hit. The lighter rate you can run, the more stored energy you'll have - but you shouldn't need anything too far different than this. If you have a 300-350lb spring up there, it's tough to pitch rotate the car.

Next time you're out, have someone video it even with a cell phone and you'll be able to see which direction the back of the car is going at the hit and it'll give you an idea of where to look with the shocks. If it is separating a lot, the rebound may be too soft to keep the tire planted. If it drops the back of the car down hard, the compression may be too soft.

Purely my opinions and input, so feel free to take it or leave it!
Mike