In the 1950s, when 4bbl carbs did good to flow 350cfm, it was common to see multi-carb set-ups as the high performance option. 8 1bbls, 2 4bbls, 3 2bbls were common on "hot rods" back then.
So, if the 426 HEMI was a 2x4bbl engine, the 440 got 3x2bbls instead. One way to get lots of air flow and a WOW affect when the hood was openned.
440/350 was the 256/260 cam with single exhaust. 440/375 was the 268/284 cam with dual exhaust, 1.74" exhaust valves, and HP exhaust manifolds. 440/390 was the same 440/375 engine with the 3x2bbl carb set-up, plus some other internal items for durability and such.
By the time the 440 6bbl engine happened, it was the beginning of larger 4bbls with 850cfm+ air flow. ONE 4bbl carb on a good 4bbl intake would make (probably) more top-end power than the multi-carb set-up AND without out the issues of blown power valves when the engine might slightly back-fire when starting. Easier to work on ONE carb than to remove the center carb on a 3x2bbl set-up.
Ford also had a 390 3x2bbl set-up for the 1962-63 Thunderbirds. A lot-production option NOT about ultimate drag strip performance. Just a bit more horsepower. No fancy exhaust manifolds, as I recall and just the normal dual exhaust under them (usually 2.0" pipe diameter). No cam upgrades, either.
Pontiac popularized their "Tri-Power" 3x2bbl engines in the 1955-'66 model years, too. But when the Quadrajet spreadbore 4bbl was introduced, they disappeared. Tri-Power V-8s could be in almost any Pontiac, even station wagons. Total airflow of those carbs was probably about 700cfm, I suspect, all things considered.
Back then, Chrysler built what I term "package cars". NOT just cars into which larger or more powerful engines went into. It was designed such that everything worked together with good results. When the car got a B/RB engine, it had different items to better handle the added weight and power of the engines. Same with the 426HEMI, including some added body bracing and such, as Chrysle knew the cars would be used for drag racing and such. Brakes were upgraded. Trans guts were upgraded (as mentioned). Rear axles might see some upgrades, too, other than just the gear ratio. Everything worked well together, which tended to make these cars "legendary performers". AND one reason that Dodges and Plymouths were the preferred law enforcement vehicles, too!
Now, there were many people who drove 440 6bbl engines as their daily cars, back then and in later years. But they also usually knew how to replace the primary carb's power valve, themselves, too. Just "part of the neighborhood" . . .
So, please advise your friend that a 3x2bbl intake set-up is: 1) Expensive to get the carbs and all of the needed linkages on the engine, plus the intake manifold and air cleaner 2) He'll (presumnig that is the correct term) need somebody to probably get it running correctly to factory specs 3) Learn how to maintain it himself as few people really know how to do them anymore, I suspect 4) Not expect a big increase in power with a bit of a loss in ultimate fuel economy on the highway 5) Really needs a good OEM+ level exhaust system under the car, plus the HP exhaust manifolds! 6) Buying "used" is not really a good option as the carb would certainly need to be kitted and inspected for "upgrades" of the prior owner 7) Not very financially viable in a $5.00+ gallon of gasoline world, UNLESS such is needed for a correct restoration vehicle which came with a 440 6bbl originally.
Just some thoughts,
CBODY67
