the thermo quad, to me, is, even above the Edelbrock/AVS are the best cross between the performance of a Q-Jet and a square bore holley of some kind......the holley build and metering system is such that if u use a carb ur not likely to produce more peak power with any other carb, however the Q-Jet and to a great extent the Thermo quad have MUCH better throttle response especially at low RPM, and their better metering almost always results in better MPG and drivability bhp for bhp produced. These also provide , especially the Carter AVS style Edelbrocks, a braoder and most often much flatter power curve than will the Holley albeit with a bit less peak power production.
To build a COMBINATION Hot rod/street rod/drag car whatever comes down to a series of sacrafices in the aim of MORE power production, the Term speed costs does not jus apply to money spent.
It costs in other areas as well, mostly drivability comfort and convienience. Be total honest with urself in ur build, decide exactly what u hope the finished project will serve as and what ur willing to sacrafice to achieve that goal and b sure that YOU can proficiently operate ur end since u can have the baddest ride in town, if u can't effectively use it ur gonna spend a lotta races reading lic plates.
a Q-Jet or Thermo Quad is a much better choice for use in a predominantly street driven application where overall perfomance is not intended to amount to too much sacrafice in drivability, and in many instances may well lead to even better performance than would the most power productive Holley u could use, the flip side is that they are a bit more finiky and complex to tweek and tune, again, those sacrafices, and, if u run other than a Mopar set-up u'll need some fgab and adapt techniques to apply the Thermo Quad, mostly the linkage.