In my experience I can't even see how any of them could have gotten through California emissions tail pipe testing.
We had that here in NYS for a while and it even got worse having to drive the car through a road course (on the emmissions dyno machine) so it wasn't even just idle cleanliness.
It had to be clean on HEAVY acceleration and you couldn't put enough fuel through it to keep up on the course to do it and if you couldn't keep up with the course, it would fail you.
I can't think of any of those 60s carbs that were clean enough to get through NYS testing here in the '70s even when they were box stock. Not one.
New York was using California numbers.
The only "Holley" clean enough for that would be the '85 Mustang GT, 4180. It will idle right around 14.6-14.7, has annular boosters but is so "clean" at idle that if you have coated steel tube headers will burn the coating right off of them.
One of the issues with the Pantera IN PARTICULAR as far as emissions, it fell under the under 5,000 units a year sold loophole as an "import".
That illiminated it from being REQUIRED to have an air pump for the exhaust system BUT it still was required to pass emissions. With those numbers it was required to be under I found that impossible to do WITHOUT an air pump.
As a matter of fact there were some cases where Ford bought back the car because it couldn't get through the emissions test clean enough to pass, but I digress.
Of the '60s carbs, the one that I can think of that was closest to a bolt on "stock" application that MIGHT have worked AS IS on a Pantera specifically would have been the '70 Boss 302 carb.
The '70 version had 78 secondaries instead of 82's on the '69 version which would probably be better with the Q stock camshaft and 5700 or so rpm limitations?
Difficult to say precisely because depending on the heads and the headers that you have on the Pantera, that factor changes enough.
That's probably a $3,000 carb now if you can find one. Why bother?
None of the Ford BB 428cj carbs are particularly well suited just to bolt on a stock Q and you have to consider the stock transmission gearing in a Pantera as well.
They are just OK, but nothing spectacular at all. Again, very expensive carbs now.
A Boss 302 Mustang with it's 2.32 first gear, 3.90 rear gears and solid lifter cam has enough differences to change calibration requirements of the carb in a hydraulic cammed, 2.20 first gear Pantera BUT similar car weight and head port configurations to the P car.
The Shelby 715 carb is another one could consider but you must realize that most of these original application carbs were intended initially for much larger cubic inch engines.
The Shelby carb was originally for the 427 medium riser single 4v application that was "re-calibrated" to put on a 289.
It, like the Boss 302 carb, were WAY to big to be great street carbs and were installed in order to qualify it as "original application rules" for the small number of those cars that would eventually be used in factory class racing.
As street carbs, they figuratively and literally sucked.
It isn't just changing the fuel jetting on them either, it is changing the idle a/f ratio by changing the "air jets" in the carbs which were never intended to be modified after they were built. That is one of the big features tuner carbs can now use. Those can be EASILY changed.
I agree on the annular boosters too. You want them. They make the carb so much more responsive and I wouldn't use anything but them, now on a Holley.
Agreed on the Holley "aftermarket 3310" as well. It is not the same carb as the original GM application BUT all of these "original application" carbs aren't worth the bother and expense now of seeking one out to use.
I knew the 3310 as the original Z28 Camaro carb.
A current "tuner" carb is a much better way to go and will save you a lot of wasted time in a "calibration" process, but it all depends on how involved you want to get into with this.
I think the only thing really to choose now is the size to go with and ultimately that comes down to what you have done to the stock Pantera engine and how you intend to use it, i.e., 600, 650, 700, 750 cfm carbs.
I can also personally verify that a Holley R-4779, 750cfm "double pumper", mechanical choke, mechanical secondaries flat out "RUNS" on a 351c the equivalent of a Boss 351 BUT, and it's a big BUT, the idle is so heavy it will smart your eyes. It's just A LITTLE BIT of a problem?
If you just want to impress people looking at the engine, buy George's SHELBY Dominator intake manifold and run the 750cfm Dominator on it.
It will run well enough.
You MIGHT just need to do JUST a LITTLE "tuning" of it though...maybe...but it WILL get you where you're going but even so, you will be pretty happy with just staring at it and not even needing to go anywhere?
It's really fast just looking at it.
Just a thought?