Yea that's it! Very cool car. And he is from Illinois.
He inspired me to go with more cubic inches so the rest of the car could be built more streetable.

Big cubes, smallish cam, tall gears.......I would steer clear of "race" calibrated carbs if you're going to buy something off the shelf.
That type of combo just doesn't need the same type of low speed calibration a more race oriented combo would, and it can sometimes be a chore to get them to run clean in the part throttle cruise mode.

While it contradicts what Russ's results were in his car, I like the plain ole 850 double pumpers in that type of application.
Custom?? I'd probably try and have something done out of the QFT "950" style body with the 1.450 Venturi.

I also like the old Demon RS combo with the 1.420 sleeves and the 1.750 base plate...... The "825", although the calibration they came with ootb was awful.

Being a dual plane intake distribution will be much better with an annular booster. Quick Fuel has 1.45, 1.50, and 1.59 venturi bodies available, I would use at least the 1.50 with an annular or a 1.59. I use BLP baseplates in my builds, the t-slot are smaller like the Holley bases and control transition fuel better, so ideally a custom is a better way to go. BLP also has billet bodies available if you want the look of billet, in either a shiny silver or a coated black version.

I would agree that if you're going to use annular boosters, a 1.50 Venturi is probably the smallest you'd want for that displacement.

FWIW, my BG set up w/ 1.425" venturi sleeves & downleg boosters ran just as quickly at the track, and noticeably cleaner on the street, than when I tested it using 1.56" sleeves & BG's optional annular boosters.

Just my opinion from limited experience, but I don't think annulars on street-driven big blocks -- even lowly 440s -- are a good match w/ venturi sizes under 1.56". Maybe I'd try something different now if I hadn't sold my annular boosters to another Moparts member, but I found that configuration hard to tune to run clean down low and it came on the main circuit too soon during part-throttle street driving.

my 512 is very close to your engine, I also have 3.23 gears 68 charger, I bought a holley 950 hp & the cruise afr was down in the high 10s, it took a lot of tuning to get it mid 13s, changed the primary metering block that has adjustable IFRs,but that was another $120.00 it works ok.

what IFR did the holley have and what did you end up with?

the adjustability of the QFT carbs is pretty appealing.

There is a 1050 QF annular for sale in the race parts section. I've never driven one of those on the street but it might work okay. If you have the patience you should be able to tune it if it doesn't work right out of the box.

the best i could tell it had .035 IFR & 70 IAB, now .028 IFR, .058 IAB

Boy, lots of options!!!!! I have the ability to get a Holley at cost so my options for other brands is a no go because I'm a cheap Mopar guy.. Does Holley make a HP series vacuum secondary carb in a 850/950? Their listings are all over the board?????

This is why I prefer to use "street" calibrated carbs for that type of application.

ANY carb(except svo`s can be tuned for the street quite easily......do it all the time even into the 8-second zone but agree the QF and newer Holleys w/billet features are nicer, lighter and better over all...........

Not that I know of. There is a 870 cfm Avenger carb #80870 but I've never used it. Might work okay on a street driven stroker. There is also the 850 Speed Demon carb which Holley sells. Not sure if your at cost deal includes Demon's or not.

If you are on a tight budget, buy a used 4781 and a rebuild kit. For less than $225 you'll be very close for a bunch less money. I did run mid 11.70s at 119.5+ mph with the 850.