Thanks both for taking the time for replying.
The engine is modified but not radical.440+0.30 ,the compression ratio is very low,Mopar alu heads and a lunati voodoo 60303 cam.I have a 750 holley vacuum sec. that i want to change for a double pump carb.

Yes ,it is hooked over the carb butterflies (ported).Right now,the initial timming is set to 16 degrees btdc.

Car runs horribly until it almost reaches the working temp.No overheating issues.
Once it warms up,it fails under heavy acceleration.Is a 4 speed ,if the pedal is violently pressed while running in second gear, it dies for a moment,makes a detonation and spins the tires .