-midnight340- Your adapter that you show is for a Quadrajet. The Thermoquad adapter has more meat between the rear flange bolts. Hold that adapter up to the bottom of your TQ and you will see the potential for vacuum leaks on the TQ base.
Ask me how I know. Edelbrock has two different part numbers, one for a TQ and another for a QJet. Although they show the same picture for both.