Dissapointing performance

To the OP: If you want to try to work the lock-up torque converter, then change your cam to a much smaller one. You have good static compression ratio about 10:1 as you said, and the DCR is not to awfully low but could be better. (I checked all your numbers and they work out to be close.) A smaller cam will match better to your torque converter and be better matched for your rear axle gear ratio. You have bought high flow heads and cam which are suited to higher RPM engine operation to take advantage of the increased breathing, but your gearing and torque converter and exhaust are set up for a low RPM torque engine.

Is this car for the drag strip only?

And BTW, your English is very good. I deal with a German manufacturer all the time so I have to be careful on how I say things so that they can be understood correctly, and not use unusual American expressions.