Thermoquad vs holley vs q-jets

Did you pick an intake yet? That will be your main factor, not many good performance manifolds around these days with spread-bore flanges and adapters are dumb.

I don't have experience with q-jets but I'd vote for TQ or Holley DP. I'm not a huge fan of VS Holleys seems like they tend to not work quite as well in real life as on paper. For a street car with auto and/or tall gears I prefer Carter/Edelbrock/Street Demon air-valve secondary carbs. What trans and gearing you running?