Dissapointing performance

IMHO:

1. The first thing I would do is the improve the exhaust since you are going to have to do that eventually to be able to use the breathing of the new heads at higher RPM's. This will be a step that you won't go back later and change. I don't think it will have a huge effect at the low RPM's.

2. The only thing I can think of to change the engine torque significantly at the low RPM's of the TC stall speed and to match the present rear gear better is to change the cam to 10-15 degrees shorter duration and keep the lift as high as you can. But this is a change that you may need to reverse later if the best drag race ET's is your most important goal. However, if you do drive this car on the road, and gas mileage is important, then the cam change will help that. If you want to stay with a solid lifter cam, I would look at the 2 smallest Lunati Voodoo solid lifter cams. You would then have to be more careful with the ignition advance to avoid detonation as you will be pushing the DCR up into the mid 8 range, and may have to limit the advance more and have it advance more slowly. Others may have better recommendations.

3. IF changing the cam seems like a waste of money, AND IF performance is the most important thing, then I would change the rear gear first. This is because in the 1/8th mile, you are not anywhere near to the best RPM range for those heads to breath. In the 1/8 mile, you need to be in the 4:1 range to get the engine to the 5500 RPM at the end of the run, and you could go a bit higher if 1/8th mile is all that you run. (I am assuming your tires are about 22" in diameter per your tire description.)

4. The rear gear change will help off the line but will not really fix the performance off of the line. Only a TC change will help. And of course it will effect trap speed; anything that makes the engine work at a lower than best possible torque will lower the trap speed if your RPM's are not being limited by the engine at the trap. Can you verify that the engine RPM's are around 4000 at the end of 1/8th mile?

5. And this is probably not the problem but are you sure the throttle is fully opening when you push the pedal to the floor?

6. I'll be curious when you check compression on all cylinders. It would be most useful to post all 8 readings.