Do I have the right carb size for my engine.

[451Mopar]

I use the K&N filtered top lid in addition to the round filter, but I don't have a scoop or fresh air intake so the intake air temps are under hood temp, not ideal for performance.
Just saying that the air coming into the carb might not be ideal, and might be a limiting factor more than carb size.
A smaller carb needs more throttle opening for driving at normal speeds, so you transition into the main metering circuit sooner and most times users only tune the main jetting.
With a large carb, much of street driving is still with shallow throttle blade opening and running in the carbs transition circuit area. most people don't tune this carb circuit, so it can be an issue if the factory calibration dosen't match your situation. These part throttle driving conditions is where EFI usually has an advantage over a carb.

 

[Daniel Brunner]

There’s a good Video about right carb sizes from UTG.
He said the easiest way to choose for a performance engine is engine displacement x2 and choose the next bigger carb cfm
Good video I learned a lot and also saw that my own carb is too small.
Link here

 

[not so famous bob]

There’s a good Video about right carb sizes from UTG.
He said the easiest way to choose for a performance engine is engine displacement x2 and choose the next bigger carb cfm
Good video I learned a lot and also saw that my own carb is too small.
Link here

I don't follow much of what your uncle says , but he "is under carbed " in my opinion ...

 

[33 IMP]

To the original question:
A 750 is an excellent universal carb size, can work on a 318-440. With the o.p.'s cam and headwork, I'd run an 850. The difference will probably show up at the strip, I doubt you'd see anything on the street, surely not $700 worth.
(I've got a race brawler 850 on mine with 440 inches, iron heads and a .557 purple shaft. And I ran an 850 on a 406 too)

 

[Moparfever65]

If it was mine I'd put an 850 double pumper on it no question.

 

[Dennis H]

850 Demon was a good fit for my similar build. Was perfect at sea level. Went with EFI due to mountain travel and Reno summer heat. Loved the Demon otherwise. 440, Dana 3:54, TKO.

 

[RJ Squirrel]

UTG likes to YAK! He actually starts talking about carb sizing at around 16 minutes.